At first it seems that this video deviates from the channel previous theme code centered indie game dev. But my channel theme is actually indie gamedev as a whole, and despite being code centric, sooner or later we'll need to face the dire need of custom assets. No bank can satisfy 100% of your animation needs, you will need to create or to buy them. In the past I thought education and creation of 3d animations takes weeks if not years, but one good soul opened my eyes on this subject and I want to spread the word now). Specifically, this video is an instruction of how to become able to produce somewhat plausible animations after several hours of training. My software is mainly Blender, Mixamo rigging tool and addon and I also will say a couple of words about Godot editor and skeletons.

The whole work is kinda a compilation of wisdom of other people, so here's a bunch of useful links:

REMEMBER YOU ARE PROHIBITED FROM CLICKING ON THEM BEFORE YOUR POSING ROUTINE!

Royal skies pose to pose approach (sort of essential):
   • Blender 2.83 : Animation Philosophy &...  
Additional helpful content from them:
   • Blender 2.8 Attack Animations In 2 Mi...  
   • Blender 2.83 : Animating Complex Moti...  

Crashsunes blender course, not so popular, but very down to earth:
   • Blender 3D Animation Tutorial  3D Vi...  
Its about 80100 minutes of blender interface guides, skip rendering in the end if not interested.

Wade Neistadts video about workflows, because workflows and pipelines are the most important things in the world:
   • The 7 Workflows of Professional Anima...  
The channel is my favourite in general, but mainly Maya content and my poor ass uses blender, so only theory from them.