The centre bolt just needs to be cracked off, so that the adjuster nut can freely rotate.
As for mixing the springs up, yeah. It happens to all of us
I think (my bikes in the garage and I can't be arsed to go and look), as you look down on the brake the gold spring is the left spring. I'm sure you'll see a pic elswhere in this section, AD setup has been discussed before.
By the way, if the springs are buckled out of shape (due to overadjustment usually) then they're scrap really. You can get new ones from Billys.