Changing a flat tire is a VERY common repair on a bicycle. Here are the steps to fix a flat tire on a bicycle. The first thing you is release the brakes, then you release the quick release . After that you use the tire lever to release all the air out of the tube then take the tire off the bead. Take the tube out and check for holes in the tube and tire. After take the air pump and shape the tube then put it in the rim . Then put the tire back on the bead. Check the psi on the tire then pump it up to what the tire says. After that put it back on the forks and reattach the breaks.