Use your hands to work as much of the second edge of the tire onto the rim as you can. It will become more difficult as you go, and finally you will need to use the tire levers to put the last part of the tire onto the rim. Do this by wedging the tire tools against the rim below the edge of the tire that still needs to go on, and then working one lever and then another to bring the edge over the rim until the whole tire is seated snugly and comfortably once again inside the rim.
Once the new tube and tire are back on the rim, do a quick check with your eyes and fingers around both sides of the rim to make sure that the complete edge of the tire is inside the rim, and that at no point is the inner tube pinched between the tire and rim or protruding over the rim.
