Welcome to the forums! :hugs:
No that is not needed, you need to place a mod's esp (and any other texture or meshes etc. folders) into the Fallout/Data folder. It is always a good idea to read the readme's for the mods. When you added a MODNAME.esp into the data folder, you open up the Fallout menu (the one you open outside the game) and click data files.
Inside the date folder, you should see the FILENAME.esp, tinker the box next to the name, and there should appear a check, just like the one for the Falout3.esm.
Now if you downloaded an armor mod, you can find the armor ingame wherever stated in the readme, or in a picture seen on the mod's download location.
If its a mod changing something like FWE or FOOK etc. (game changing mods) they should already have their effect kicked in. No "COC modname" is needed at all.