I mean does it have something to do with its performance in recent years? I'm guessing it does cuz Roma won Serie A and is not one of the seeds while Juve finished runners-up and is seeded. Liverpool is also seeded and well they finished third in England. So could someone explain how a team gets seeded. Thanks.

IIRC from the last 5 year Europan Cups results.

Basically teams are given seedings the same way as tennis and the world cup. the teams that have performed well in europe over the past seasons are given seedings, not how well they performed in their respectie national leagues, that only decides qualification. For example Liverpool finished 3rd in the premier league, yet won the uefa cup, so they won in europe, thus have a good european record which is how uefa decide the seedings.

Then why are Barca seeded, when they have done **** all the last couple of seasons in europe?

FifAustralia is a bit wrong, every country has a place for a european cup in europe. England had top 2 finishers garanteed a place in CL and the 3rd place will be in CLQ. Same thing with Spain, but i don't know how many places Spain has for CL. For example, when a team in italy finishes in top 2, then he will be automatcly in th Cl and 3rd and 4th place, will go to CLQ. But if a team won a CL, then he will automaticlly play in CL next season, even if he will finish in the last place in the league. It's not on records, it's epends on what place you got in your country and when your countries teams are doing pretty well in CL, they get more places to be there, like last season, at the end of this season, there will be 4 top places, that a teams can get to play in the CL.