Modding Help New monster without replacing old

In the title. I want to add a new monster without replacing an old one. I made a test monster and it works fine, spawns in the world and does what I wanted, but it replaces an already existing monster. I'm pretty new to modding so if someone could just point me in the right direction that'd be great. Thanks!

 

I've never tried this but you could just rename the testmonster folder to whatever the monster's name is, and get a new realmonster folder? Like if you used poptop or gleap as a base, get a new folder of that type, and put it back?
If you tell me what the monster was, I'll post instructions for replacement!