After you place the top pie crust on, trim the edges of both crusts evenly, leaving 1/2 " overlapping the pie plate. Fold the 2 crusts under 1/2". You can now do your decoration. To flute, just take your thumb and pointer finger of one hand and the pointer finger of the other hand, and pinch them together. If you don't want to flute you can take a fork and press down along the top after you have folded the crusts underneath. Make sure you vent pie crusts with a sharp knife by making 1" slits several places on top crust.
Notes
You can use your favorite homemade crust here as well.