First make sure that the needle is fully up. Then you need to open the hinged front cover and unscrew the needle plate screws. Remove the bobbin. Brush out any lint now. Remove the bobbin case. Then snap the hook retaining arms outwards. Remove the hook cover and hook. Put no more than 2 drops of sewing machine oil on the the case (center right hand side). Then turn the hand wheel until the hook race is in the left position. Replace the hook and then the hook cover. Snap the hook retaining arms back into position. Replace the bobbin case and bobbin. Then replace the stitch plate.
Test the machine on a piece of waste fabric. If the hook keeps jamming, take the machine in for maintenance. The parts that may need to be replaced are the race or the shuttle hook. However without seeing the unit I do not know if there is not another problem. Some parts for the 2263 are available here: http://www.sewingpartsonline.com/singer-2263-sewing-machine-parts.aspx
Singer has a second manual available with the oiling instructions for the 2263 here: http://www.singerco.com/uploads/download/1213_oiling-2263.pdf
. See the diagrams on this page for where things line up. The rest of the instruction manual is also online here: http://www.singerco.com/uploads/download/1180_2263%28eng_spa_fre%29.pdf
I hope this helps.