I sponged the edges and set them aside . I used Scotch tacky adhesive and applied a generous amount ( not too much , not too little ) to the front on the frame , lined up the cardstock and gently pressed it to the frame . Allow a few minutes to dry .

Question: What may have happened before I did this ?
Answer: I attached it to the frame .I sponged the edges .I put it on the wall .I found cardstock I like .