This should cover the (very) basics well: http://www.teachmtg.com/basics
If you want a video, something like this should cover the bare-bones basics: https://www.youtube.com/watch?v=RZyXU1L3JXk
Once you have a sense of the basics, the best way to learn is to play and look up rulings whenever you get stuck.
Basic official rules are here: https://magic.wizards.com/en/magic-gameplay
Comprehensive rules for the current season are here: https://media.wizards.com/2019/downloads/MagicCompRules%2020...
Whenever there is a ruling specific to a card and its non-trivial interactions, you can look the card up in Gatherer, and there will be a rulings section that will tell you the relevant info. For example, if you were using the card 'Felidar Guardian' and didn't know what would happen in a particular case, you'd look up its Gatherer page: https://gatherer.wizards.com/Pages/Card/Details.aspx?multive...
Be warned, mtg is addictive and expensive.
If you have a local game store going in and asking if they have any resources for new players hoping to learn how to play would probably be the best option, imo.
Boardgames are social thing. Magic is the best when there is a gathering.
the good news is that you don’t need to learn all the rules. you learn the basic rules and after that you learn the rules surrounding abilities/effects/etc as they come up.
here:
https://magic.wizards.com/en/game-info/gameplay/rules-and-fo...