Putting them back on is easy.
I do want to warn you that there will be residue from the double sided sticky tape that exists between the back of the two piece mirror (actual mirror and black trim are one unit) and the mirror housing.
I did use goo be gone (but gas or alcohol works just as well) to remove the residue so the new double sided sticky tape would have a fresh surface to adhere to.
Anyways, when it comes time to instal (that is the easiest part). The upper hooks on the back of the mirror insert into the slots at the top of the mirror housing. The hooks insert into the housing at a 45 degree angle so you must angle the mirror and then once the hooks are into the slots just bring the mirror to a vertical position.
Then (remember that the entire mirror will be put to a forward lean prior to removal) you put both your thumbs on the mirror glass and both your middle and pointer fingers on the back of the mirror housing unit - as in on back of the same piece of plastic that you slid the upper hooks into.