You need to wait for a sunny, warm, low humidity day, then paint or stain the door and jambs. Don't forget to paint or stain all sides of the door...bottom and top.
Then check the door for fit before you seal it with a polyurethane. If it is ok then finish it. If not, now is the time to adjust the door jamb a little first. Try a longer screw in the hinges, but don't let it bind. You want a 3/16 ths gap around the top and sides. Last resort is to then plane the door. Then when it works good. Finish the poly if you stained the door.
Hope this helps out. Good luck.
If I missed something someone will be by shortly.