I'm sure you've all see these and probably know how to make them, but just in case I thought I'd share how I made the magnets to go on my bulletin boards.
Step 1: Gather your supplies
-clear decorating marbles that are flat on one side. Mine are about 1"
-scraps of printed paper
-paper punch as close to the same size as possible to your marbles
-E6000
-magnets and/or tacks
Step 2: Start by cutting out circles of paper. My paper punch is just slightly bigger than my marbles, you could trace your marbles and cut out a circle, or cut circles on a Cricut for more accurate sized circles
Step 3: Glue circles to the flat side of marble using E6ooo. Let try a few hours to overnight. Can you tell in this picture that my paper circles are slightly bigger?

Step 4: If necessary, once glue has dried, trim excess paper from around marble using a exato knife
Step 5: Glue magnets or thumb tacks to the back of the marble using E6000. Allow to completely dry.
Attach to fridge, cork board, magnetic board etc. and enjoy your custom magnets