The best thing to do is get it a a u-pull-it yard, there you can rip them off the donor car, see how exactly they were attached so you'll have a better idea of how to put it back on.
2 years ago, my molding was falling off because of the small plastic clips being broke, there like an inch long and a half an inch tall and look like this
from the side
There really cheap at the dealer like 10 cents or so.
Youll be able to see how they go in once you have the molding off.
They slip on the molding and into the horizontal brackets that go across the middle and bottom of the door. There are also two screws at the bottom of each door on the inside that hold the bottom horzontal bracket in place.
It'* really hard to explain sorry if i confused ya.