You can find your supplies at most craft stores in the kids section or check at a nearby thrift store that carries craft supplies (that's where I found mine!). I've also heard that they carry them at Ikea but can't confirm it. There are all different shapes of peg boards but for these I used the big hexagon pictured.
Step one is to place your beads in the pattern you want on the board. Pretty simple. The patterns I used or altered are this one for the snowflake and this one for the other.
Be sure not to iron on your peg board or it will melt. Unfortunately that's what happened to this thrifted peg board.
While still warm, set something heavy on top of your design to prevent it from curling up while cooling.
Once it's cooled completely, take it off the peg board. I know some people prefer to have both sides melted, so if that's you, turn over your design and repeat with the paper, ironing, etc.
I personally like the beaded look of the other side so I left my right side unfused. And there you go! Cute coasters that are inexpensive and totally customizable. Have a great weekend!