Its the same as any other conversion/port process.
Get your models, export or decompile them into viable format using tools required for that type of game, use like a modelling software to convert them into .smd formats, compile them, and load them into SFM.
There is technically no such thing as an "SFM model," its all Source Engine. Source Engine models will work in SFM, and SFM models should work in any source engine game.
As far as I'm aware SFM still uses SDK 2007, not 2013. I could be wrong.
I won't give a tutorial on that, too much to go over.