Making refrigerator magnets is a simple process. Just glue magnets to something that you think would look good as a magnet and wait for the glue to dry. Epoxy works best, but for certain materials hot glue may also work.
Find something to glue your magnets to. For example, individual tiles from a 12 x 12 ‘mosaic’ tile.
Or, glass beads.
Arrange, glue and let dry.
You may want to think about how to keep bubbles from forming and being permanently set, especially in transparent fridge magnets like this one. Either be careful when applying the glue, pop the bubbles with a toothpick, or use a glue that tends not to form bubbles when applied.
Larger magnets, while very effective at securing large amounts of paper onto a fridge, tend to scratch the surface of refrigerators over time by collecting ferromagnetic dirt, and by being metal objects sliding over other metal objects. For this reason, smaller magnets are usually better for refrigerator magnets. Or, if you must use large magnets, be mindful of their tendency to scratch fridge surfaces if paper is not between the magnet and the fridge.