Hi Deepak,
I would mirror what the others have said.
The older Piero course is excellent, but if you get stuck because of any changes, don’t forget you can ask questions (or read the questions that have already been asked.)
The https://cgcookie.mavenseed.com/courses/rig-and-animate-a-treasure-chest-in-blender-2-8 course will show you some more concepts for a simple chest character with squash and stretch. (not the style of character you are asking for though – I know)
Pierrick’s rigging course is very good (very much ‘from scratch’), as well as Tudor’s (CGDive) Rigify Course (Rig anything with Rigify)
The latter uses the inbuilt rigify addon so it’s not ‘from scratch’, but even if you plan on using rigify I think it’s a great idea to understand the basics of rigging first.
Hope that helps.
