I then figured out what size the letters needed to be to be centered on the frame I used the cardboard piece that was in the back of the frame and just mod podged the scrapbook paper to it and trimmed of excess with a craft knife.
Cut out the letters and arrange them on the board in a pleasing way.....hopefully centered :) Once I got it to look the way I liked it ( I used a cutting mat as a ruler and guide for a straight line to glue the letters permanently on) I brushed on the Mod Podge on the back of each letter. Stuck them all down. Waited for them to dry a little. Then I gave each letter a good topcoat of Mod Podge.
All that's left is to ( clean the glass first ) stick it back into the frame and for a little whimsy I hot glued a felt flower I had made for my daughters hair but never used.