When I download a mod they tell me to put it in for example: \data\meshes
But I don't have \meshes. I only have "Skyrim - Meshes.bsa"

My \data looks like this:

imgur(.com)/V1YVf

Any help?

The Meshes directory can be created by the user and things will work fine.

However, it's much simpler and actually safer to use one of the various mod managers to install mods.

If I create the Meshes folder, do I need to extract "Skyrim - Meshes.bsa" in said folder?

Actually, it's better that you install them manually. If some folders are missing, like "Textures" or "Meshes", just create them. Follow the instructions in the "Read-me" and everything will be fine.

No. Same thing for the Textures.bsa or any .bsa file present in the Data folder. Never touch any of them.

No

Uh, it's really not.

For instance, if you want to remove a texture replacer you'll need to go in there and manually figure out which files belong to what and then delete them one by one. This can be hundreds of files or more.

Thanks for all the help guys! It works.

Sure, I've done that hundreds of times ever since Morrowind. Never used any mod installer. If I made an error, well, I fixed it. Anyway, most modders put their textures and meshes into bsa nowadays.