A picture is worth a thousand words:http://www.beesbythesea.com/Bees_by_the_Sea_Apiary/Photos/Pages/Removals_2008.html#19
I brush off the bees, cut the comb to fit (I try to get it to fit tightly, so there is just a bit of resistance putting it into the frame), put the rubber bands on the ends of the frame, hold the comb in place, and then slide the rubber bands over it. You can do this yourself, but it helps to have an extra pair of hands.
Brand new combs are very flimsy and easy to crush. You have to be very careful with them.
You can find a lot more pics in the removal forum.