The first step is to drill a hole in the center of your woodblock. This is where the bolt will be tightly screwed. You'll have to pre-drill this hole before screwing the wood into the block. Insert the block of wood into the wheelchair's frame. Again, be sure to check that you are clear of any electronics or mechanical things that might interfere with the wheelchair's operation. To secure the woodblock, you will need to drill a single hole in the top of the frame of the wheelchair, and secure the block with a screw that goes through the chairs frame and into the woodblock. Wheelchair frames are very strong... be sure to use a very good drill to make this hole. Screw the woodblock so that it is firmly positioned into the frame of the chair.