If your chicks are getting burned, it's too hot. I would suggest investing in a thermometer - I have a temp gun that I love, but they're about $40, and a typical sensor thermometer for outside will work almost as well, so long as you don't have chicks lying on it.
If you don't have a thermometer, the best way to tell if your chicks are too warm or too cold is to watch them. If they're too warm, they'll try to get away from the heat lamp (there should ALWAYS be a gradient of temperature in their brooder - warm on one end, cool on the other), pant and look uncomfortable. If they're too cold they'll all be clustered right under the lamp pretty much dog piled on top of each other.
The ideal temperature will have the chicks wandering about the brooder each doing their own thing and dozing wherever they're comfortable. They may form chick rafts when they sleep, but they shouldn't be a constant huddled mass.
90-95 for the first week is about where you want to start, and then decrease by 5-10 degrees for every week.
Hope this helps!