Creating custom models

Apologies in advance if a thread already exists, but having searched the internet, Gmod wiki and Youtube videos for a good couple of hours, i have now resulted to appealing to the gmod community for help. I am trying to learn how to create and import my own models in the Gmod, any information or a simple link to a guide would be greatly appreciated.

Thenewboston covers 3ds max modeling.
After you get the hang of that, just download an SMD exporter plugin and GUIStudioMDL, make a qc and compile your model.