You don't really need the other folders as long as you have the pcs/pac file which contain the textures. The other folders are for stuff like custom names and character select portraits. But if you want those, download Brawlbox and go
here he has some good Brawlbox tutorials. Just check out the basic stuff videos and then you'll know what the folders are for.
yes it does matter unless you have Riivelution which idk if he has.
ok so if you do not have riivelution the basic folders you need are easy. the basic folders for brawl go like this. each folder goes inside the other.
privet/wii/app/RSBE/pf. And in the pf folder you have the 2 main folders called fighter and stage. Fighter is where you put all your textures and different movesets or PSA's. The stage folder is where you can get textures for stages or entirely different stages. In the fighter folder you will have one folder for everyone in brawl. But they are not just called what they are in brawl. some of them are but some of them have nicknames. Inside the folder of that character you put the files for textures and stuff. Do you know how to rename the files and everything? If you have anymore questions id be glad to help.