The first step is to paint the sides and backs of your paper mache letters. I used inexpensive acrylic craft paint. You could also use spray paint if you wish. Allow paint to dry.
Next, lay out photos on top of each letter and determine which photos you want to go where. Snap a picture with your phone that you can refer to as you start adhering photos.
Start with the first photo and place it where you’d like it to go. You can use a paintbrush to dab a bit of mod podge on the photo and stick it to the letter. Then flip the letter over and trace around it on the back of the picture.
Place the picture back down on your letter and grab your next photo. Determine if you need to trim any portion of the first photo to make room for the second picture (I cut about an inch off the bottom of the picture I’m holding above).