and make sure the esm has absolutely nothing that edits another esm's records

It's fine to do that if you modify worldspace data in your ESM afterwards with Version Control, for some reason it fixes the disappearing land bug.
I'm actually going about changing it to an ESM so I can do the whole Version control thing, from Maegfaer's tutorial but I edited some Vanillla Leveled lists and a few Vanilla NPCs.
I want to separate my changes into their own esps though, so what's the right procedure to turn this into an ESM and split it properly and all that?
Any help here would be extremely appreciated since I haven't the slightest damn clue what the hell I'm doing.
I'm currently at this step:
Copy Skyrim.esm and one or more of your own ESM files to Skyrim\Merging\Data.
I dont have an ESM file so I have to figure out how to make one lol.