Replacing door track on 320

It’s time to replace my track. I found some threads and know the parts. Can someone advise the method/order of putting it back together once the door is out? It seems the track and trucks need to be already on the door before attaching to the boat? Or not?
mid not how difficult is it to attach the trucks when they are already in the track?
Thanks

If its the problem you having from the door sticking I don't think its your track. I used to have the 320 and looks to me these doors warp... If you close it ur see it rubbing in the middle somewhere... Dbl check that before you change all the Tracks and rollers.

Thanks. My track has partially broken and the trucks have fallen apart. It’s time lol!