Help with models

[S.W.A.T.Y]

I have downloaded some of the models from the thread "share models" and I dont know where to put them, When I open them in hammer i dont see the model, I can search for the name of the model but the model doesnt show on the screen, its just blank. can someone tell me where to put them or how do i use them in source sdk, im trying to make a map for hl2 ep2.