The key idea is to heat the records enough to soften them and make them pliable without causing them to drip or burn.
To begin, place a bowl upside down on the baking sheet, and set the record on top of the bowl.
Place the configuration in the oven, and heat to to anywhere between 90° and 120° C. (200° to 250° F). The record should take about a minute or so to begin melting.
After the record begins melting, leave it in the oven until it is lying against the sides of the bowl. At that point you can take it out and let it cool. Now you have a simple bowl. Of course you don't want to leave the oven door open the entire time, I've just opened it for the sake of these pictures. In practice you should be watching anxiously from the kitchen floor :)
Another method is to put the bowl right side up, and allow the record to melt down into the interior of the bowl. Try both methods and see which results you like best, or try some of the techniques discussed on the next page.