Do you want to learn how to port models but don't know how? Either because 3D modelling is daunting, you don't know how GMod or SFM works, or you don't know where to get the models in the first place? I hope this tutorial will help guide you through the process.
Texture details are explained in part 2, over here:
Please let me know if there are details in the porting tutorial that require more explanation. I'd love to make this as clear as I can for everybody and it's hard to do without remembering how it felt when this was all new (also admittedly pretty late as I write all this so I'm bound to have messed something up).
A major difficulty with porting is finding the required tools for importing, extracting, and converting, not to mention with free programs. Every tool required are included with links directing you to their source.