Best site to play on: https://lichess.org/, free and with really nice features to study and learn. It is not-for-profit, funded by donations and has the best UI and feature-set, without the annoying popups trying to sell you some premium features.
Specifically, lichess has a very good tactics puzzle section. It also lets you review your games with an engine afterwards. If you solve tactics puzzles, play games and review mistakes this will help a lot to improve at early stages, I would actually recommend against trying to learn specific opening theory too much at the beginning.
If you want to watch Youtube for fun, here are some nice channels:
Agamator does clear explanations of elite games. He has famous 'captures, captures, captures' statement when there is a long line of captures.
Hikaru Nakaumura is one of the top 10 players in the world at classical, and blitz chess. He streams games played against other elite players, fun games he plays against fans and lessons he gives to famous Youtubers. These are all fun to watch.
Chess-explained is a German international master who is very keen on studying openings. If you watch his videos you will get some interesting insights into chess theory. His 'D4 repetiore' series was helpful to me.
I can't say I have improved much by passively watching Eric Rosen videos on youtube but I have definitely thoroughly enjoyed it! He has a super relaxing voice and is incredibly good at explaining his thoughts while playing https://www.youtube.com/channel/UCXy10-NEFGxQ3b4NVrzHw1Q
Specifically, lichess has a very good tactics puzzle section. It also lets you review your games with an engine afterwards. If you solve tactics puzzles, play games and review mistakes this will help a lot to improve at early stages, I would actually recommend against trying to learn specific opening theory too much at the beginning.
If you want to watch Youtube for fun, here are some nice channels:
Agamator does clear explanations of elite games. He has famous 'captures, captures, captures' statement when there is a long line of captures.
https://www.youtube.com/user/AGADMATOR
Hikaru Nakaumura is one of the top 10 players in the world at classical, and blitz chess. He streams games played against other elite players, fun games he plays against fans and lessons he gives to famous Youtubers. These are all fun to watch.
https://www.youtube.com/channel/UCweCc7bSMX5J4jEH7HFImng
Chess-explained is a German international master who is very keen on studying openings. If you watch his videos you will get some interesting insights into chess theory. His 'D4 repetiore' series was helpful to me.
https://www.youtube.com/c/Chessexplained/videos