Paint the canvas with one coat of a cream colored paint of your choice. Set it aside to dry.
Cut 3 pieces of elastic cord, about 9-inches each. Take one of those cords and thread a medium sized bead onto the end. Run the cord back through the bead and second time and tie a knot. Turn the cording so that the knot lines up with the hole in the bead. This will allow the end bead to hang correctly with the rest of the beads.
Thread beads onto the cord however it pleases you. I varied sizes, putting 4-5 seed beads in between the larger beads to give it variation. You want to have about 4-5 inches of beads on the cord. Tie off the final bead by running the cord through the bead twice and tying. Repeat with the other two cords.
Position the beaded cords on the canvas. I found it easiest to tie all three together at the top. Once you know where you want them, trim any extra cording from the bottom and top and tack down with hot glue. Hot glue the shell over the top of the bead cords. Hang!