Emerald takes the following out of the group inventory: an Entropic Shard, a Cinder Fruit, the Everlasting Apple, the totally-not-a-deathtrap Retcon Orb, 8 Iti Fragments, 75 Glitch Gel, 1 Cinder Log, and 50 chunks of tiny meaty abyssal ornstein.
He starts out by examining each item individually, seeing what they were made of, their properties, et cetera
Entropic Shard: A fragment of entropy. Emerald knows he's being stupid to use this, but if it doesn't kill him, repeatedly, he will have successfully tapped into the power of entropy for an explosive. Totally not a stupid idea
Cinder Fruit: Some weird fruit, which explodes into fire. Provided he doesn't accidentally drop it on to something sharp, it shouldn't go off, and is probably one of the safest things in this recipe, which is kind of stupid considering the fact that it's some fruit that has literal fire inside it
Everlasting Apple: an apple which regenerates itself. Safe enough, except that it explodes. Emerald will be figuring out how to harness both the regeneration and the explosion for this incredibly stupid idea that he's going through with anyways
Retcon Orb: this is the (main) wild card of the situation. Not much is known about this to anyone who's not WARE, and unless Ire helpfully pops in with some hexadecimal about the nature of the orb, the following shall be assumed: If this is set off early, the progress that we've made, overall, and in this crafting recipe, will be set back, who knows how far back. This works by reversing both time and the influence of someone's decisions who's caught within the blast radius. Hopefully the entropy and this will harmonize in order to minimize the overall danger to our progress and the danger that naturally comes from fucking with entropy. If it works correctly, the singularity will constantly be reversing its own progress of the Heat Death of the universe.
Iti Fragments: another wild card, but this one is mostly due to the fact that Emerald wasn't around to fight these guys. He's basically including these because they're purple and look ominous.
Glitch Gel: one of the less dangerous items, mostly because they burn out so fast. Emerald will be attempting to harmonize these with the power or Retcon in order to un-Burn themselves in order to continue constantly burning.
Cinder Log: Arguably the least dangerous items, because it's ‘simply’ on fire. Why not add some flaming shrapnel to our danger cocktail?
Ornstein Chunks: small chunks of some guy, with latent power inside. Emerald will be using these in tandem with the Entropy in order to fuck things up

Now that that's done, the actual crafting can begin. Emerald carefully takes the Retcon Orb and gently sets it on a convenient nearby pillow. After that, he takes the Glitch Gel, and, with great patience and care, slowly begins covering the Retcon Orb with the Gel, covering it completely with about 2 inches of gel.

With this, he takes the Cinder Log over to somewhere safely far away from the Retcon Orb, and begins hacking it into tiny slivers, which he collects in a bucket.
He takes the bucket back, and sets it about 3 feet away from the Retcon Orb, mostly because there's the possibility of accidentally setting the Glitch Gel on fire.

Now for the part which would not be very dangerous: Examining the apple.
Emerald sits down on a convenient tree stump that's somehow there for him to sit on, and examines the apple, occasionally taking bites out of it (the bites regenerated), slicing off pieces (the pieces stayed detached, and then the apple regenerated), and slicing it in half (ending up with an apple and a half, although the half didn't regenerate for some reason, which he then ate). He presumes this to mean that there's something in the core of the part that regenerated that allows for the possible explosion and regeneration of the apple. He cuts it in half and then cuts out the core, at which point he sees….something. He's not sure how to describe it, it just doesn't look right. He doesn't know why an apple of all things would have an eldritch thing inside it causing it to regenerate, but he won't complain, it'll be helpful. He takes the...thing, and throws the apple away, cutting off apple parts when the thing tries to regenerate the apple, before putting it inside a small box, at which point he notices it doesn't try to grow the apple. So if it's enclosed within a space too small for an apple, it will not regenerate the apple. That's...oddly helpful.

He takes the thing in the box over to the rest of his equipment, and sets the box next to the Glitch Gel covered Retcon Orb, and prepares a spell, similar to that of Shifting Sands, which obeys the Second Law of Safe Teleportation, but on a smaller scale. A much smaller scale. The spell is complete, and he casts it, switching out the center of the Retcon Orb, exactly equal to the size of the thing, with the thing. Now that should cause the Retcon Orb to regenerate constantly when it explodes from...explosion.

Time to see what these meaty chunks do.
He takes the fifty small chunks of Ornsteins flesh, and puts them all into a large bowl, which he then smushes them all together into a large mass of meat. Now then, the meat is infused with Abyss somehow, and he's looking to take that Abyss out of the meat, which is probably one of the only things that can safely(?) contain Entropic Shards, as there is nothing to Entropy if there is nothing. So, of course, the logical thing to do is to fry it. He takes the large blob of fleshy meat and sets it up on a grill, inside an airtight bubble, to contain the Abyss. And then he starts burning the meat. Due to physics, the empty space known as the Abyss infused with the meat will disappear, when the areas filled with Abyss is filled with hot air. And so it does, with a black empty cloud of whispy wind forming in the top of the bubble. When the meat is completely de-Abyssed, he turns off the Oven, and shrinks the airtight bubble until the Abyss solidifies due to compression. Now he has a ball of solid nothingness. Yay?

He takes the bubble filled with nothing, and the Entropic Shard, and then inserts the Shard into the bubble, as well as all 8 Iti Fragments. He reforms the bubble into a cylinder, with the Entropic Shard in the center, and the 8 Iti Fragments in the shape of the 8 points of a cube around it.

All that is left is the Cinder Log splinters. The easiest part. He takes the Cinder Splinters, and the cylinder of totally-not-dangerous things. He uses Cinder Splinters, and liberal application of superglue to form a shell of flaming wood around the Cylinder. It is complete.

All that needs to be done is, when the time is right, to set the Glitch Gel Retcon Orb on fire with the Cylinder, which will then Retcon the Cylinder, causing the Entropy Shard (and Iti Fragments) to release their latent energy in a violent explosion, which shatters the Retcon Orb, only for the thing to reform it all to explode again. And again, and agai- you see my point.