There are some good YouTube channels that go into this. EEVBlog[1] has made a lot of really nice videos about the fundamentals, as has w2aew[2]. And I found MicroType Engineering[3] to be a good source of practical information on designing circuits.
Capacitors next to ICs are almost always for decoupling[4]. Similar to how the cistern in your toilet provides a large amounts of water in a short amount of time without affecting the water pressure in the rest of the house, hence decoupling the local water flow from the main supply, decoupling capacitors can supply a lot of current for a short amount of time.
However what values to use can seemingly be a bit of a black art[5], not helped by the fact there's so much outdated information and rules of thumb out there from the days of through-hole components which just doesn't apply to modern surface mounted components (like needing multiple different values).
On the other hand, resistors on a data line can be there to protect against ESD events[6], for example.
Some of it might be a bit more advanced than what you need right now, but there's definitely some good stuff for people starting out. If for nothing else highlighting areas you should be aware of.
[1]: https://www.youtube.com/@EEVblog/playlists
[2]: https://www.youtube.com/@w2aew/playlists
[3]: https://www.youtube.com/c/MicroTypeEngineering
[4]: https://www.youtube.com/watch?v=BcJ6UdDx1vg