Rigging is actually not that difficult, there’s default rigs available in 3ds Max like Biped and CAT (Character Animation Toolset)
Weighting, is more difficult, at least for me I’m not very good at weighting the mesh. I used Mixamo and it gave me better results than what I’ve been able to do. Ultimately it comes down to using the Skin modifier and learning how best to setup the weights so that things deform properly.