Copy in Minecraft texture pack?

Me and my brother are doing a Minecraft texture pack right now. But we don't have an "entity" folder for the texture package that we're modifying and we wanted to copy it from another texture package. Unfortunately, that doesn't work. I can't change any other folder to "entity" either. So I wanted to ask why this is not possible and whether it can be avoided.

That doesn't work you have to copy it into the recourcepacks folder beforehand, then copy the entity folder from there that texture pack

You can also create an entity folder. Or is that the problem?

No, that doesn't work either. I'll try again later, then give feedback