f2s stronghold models?

Hello, I have recently donated to RoaringCow and received F2S Stronghold, I am trying to add custom props etc to the server I have tried to do it so it adds a model from content/models/CustomProps/sandbag.mdl, it adds to the menu, but it is an error, although the model is there and the client also downloads it. I was wondering where the models/player folder is, as that is where the default skins are located, I have set it so it shows hidden files, but I am still unable to find the folder.