Glue your paper to your frame. Mod Podge is ideal for learning how to decoupage, but you can use Elmer's School Glue if you happen to have some available. Apply the glue lightly and smooth out any air bubbles with a popsicle stick.
When the glue is dry, lightly run over the edges of your frame with fine grit sandpaper to smooth down any rough edges. If desired, ink the edges of your wooden frame to give it a bit of a vintage look.