Had the same issue last year, didn't see the
guide on lee's link but it's s good one. I just got a box of door seal cord from SEAT, I think it was about £20, which will do all doors and some.
I ended up having to replace my window regulator clips so took the opportunity to replace the door seal when the carrier panel was off.
All I will say is the front doors are a joy to do compared to the rear doors..lol
Had to do them when replace door lock modules.
There is some good guides on here to ukmkivs site.
No more steamy windows or wet carpets since. So well worth doing the lot, if you have the time.