Move on to the next tube in the line. Examine the tubes and match them as close as possible to their neighbors. You may also need to rearrange them once or twice to get them to fit together properly.
The spacing is snug, so be patient, and careful. If you are installing optional INS-1 neon lamps, you may want to place them in at this time, to get a good spacing for all the elements on the board. Remember, do not solder anything at this time.