1. Use a jigsaw to cut out the side support pieces in a decorative shape. Attach to back piece. You can use 1-1/4" nails and glue or screws to attach.
2. Use screws to attach bottom shelf to supports and back.
3. Use screws to attach a pair of sides to the bottom shelf.
4. Continue working upward, attaching the shelves and sides, with 1-1/4" trim screws and
5. Finally attach the top to the tree, using screws and glue.
6. Hang on wall.