I watch LoL(LEC and MSI/Worlds mainly), but I don't have much clue either but this is how I understand it (at least LEC):
You have 2 splits split into 4 seasons aka Winter, Spring, Summer, Autumn(?) and pretty much during those you collect points to have better chances at making it into Worlds in end of the year. Also after 2nd season of the year(Spring) top 1 or 2 teams from each region qualify for MSI that is like Masters international event.
And before that you have regular season where teams regionally play BO1s against each other and then top 8 qualify for groups and then top 4 qualify for playoffs and those are BO3/BO5 nowadays I think.
I'm not exactly sure about everything and they just changed how LEC works. Also if I'm not wrong the format depends on region. But I'm pretty sure I got it but not exactly sure how points work.