TRY TO USE THE EDIT BUTTON! But yeah..most of them are up for grabs or either not finished or just for show. When you d/l a model. Put it were its designated. If the name is different but the readme tells you were to put it, rename it the model name and replace the current one.
lets say you download a ssj3 goku model, and its titled ssj3goku. just go to c: sierra/halflife/esf/models/player fine the ssjgoku folder. and copy that to your desktop, you should backup any models you replace, just a tip.
after youre in the ssjgoku folder and the ssjgoku.mdl is gone, paste the ssj3goku.mdl and rename it ssjgoku.mdl
in shorter terms. you have to rename the models to the model that youre replacing. and put it in the folder of the character youre replacing.
yeah you have to replace. thats why i said to backup all your stuff. i made the mistake of not backing up stuff one time and i was really screwed. but if you accidently deleta a model or just forget to back it up, just enter a server and the models that youre missing will aotomatically download. or as for them, im sure someone will help you in that sort of situation.