To make this bike rack you will need:
-an old baby bike seat (looking online it seems like most will work for this)
-a small sturdy wire rack (I got mine from an old camping grill but a small microwave oven rack or any sturdy wire rack would work)
-a few zip ties
-some paint if you wanna make it look nice
I apologize I don't have any pictures of the raw materials because I made it a few months ago, but a quick search of google images shows all sorts of baby bike seats that look similar to what I used.