I don't know if you remember, but Arsenal are in the Champions League. Again! That's, what, 94 consecutive seasons? Well, no, not really. I've told you a million times, don't exaggerate. This is the 18th season in a row that Arsenal have qualified for the Champions League group stages.
Anyway, this season's CL qualifiers finish today. Tomorrow, a bunch of ping pong balls get dumped into four shiny silver bowls and then taken right back out again, and those balls will determine Arsenal's Champions League group.
The seedings have changed for this season - Pot A includes the winners of all the major leagues, plus the previous season's CL winner. This year it also includes Eindhoven, because Barca won both La Liga and the CL. Pot B includes Arsenal and a bunch of other randos, including Real Madrid, and pots C and D include the other 16 teams. Teams can't be drawn against other teams from their own league, but otherwise it's an open draw.