Step 3: Lay things out - Glue it down!
Once you're satisfied with your layout, start gluing things down.
After laying it out, I decided I wanted to put a ribbon on it so I put the ribbon (backside up) on a scrap piece of paper and then rolled the double stick tape dispenser over it while holding the end down. The ribbon then becomes a sticker-of-sorts and you can just stick it wherever you want. Trim any ribbon that goes over the paper (tip: use sharp scissors and turn the paper over).
This is the roll-on tape I used: