What you need:
sandpaper (not shown)
jute or ribbon & drill (also not shown)
1: sand your slice down!! Especially where there are knots. The smoother the better
2: outline the edge with paint first, then fill in the middle. Let dry. Repeat 2 more times or enough so that the wood is filled in.
3. Break it in with some chalk FIRST!
4: Then add artwork, drill a few holes, and the string some jute through and tie to hang.