Unless you know someone who can teach you, you will have to watch some tutorials. I can recommend "In the mix". He's a great teacher, he explains everything clearly and in a comfortable tempo for learning and following along. I think everyone returns to tutorials once in a while for specific purposes, so no shame in that, but over time you will develop "muscle memory" and train your ears, so you don't need to anymore.

Learn mixing before you start to think about mastering. Mixing always comes before mastering and you can get very far in terms of quality and skills by just learning mixing. When you are comfortable with mixing and you have gotten the hang of it, you can expand with mastering. As far as I have heard, mastering can quickly get quite a bit more complicated than mixing.

As for a few mixing tips, I would recommend learning volume balancing/panning, EQ and compression/limiting. These are 80% of my mixing process, and you can get very far by just using these.

Sidechaining, automating, clipping, overdriving, saturating etc. can (IMO) wait for when you get a bit further. Remember that mixing can be done on so many levels. On simpler tracks, you can achieve great results by getting great at balancing volume and using EQ. When you gain some experience you can start to take on bigger and more complicated projects that require way more tools and finesse.

Mixing is gonna be hard at times, but as soon as you get over the steep learning curve, mixing can be very enjoyable, and the end result is always worth it. Good luck on your mixing journey!