The lift handle is used to lift the motor arm and idler arm for arrow shaft insertion. The idler lags about a half inch below the motor arm when lifted this in this manner. This is expected.
Note - many arrow builders prefer to insert and remove arrows with the crester running without lifing the arm.

The tension spring can be moved side to side for best function. Normally the crester works best with the spring near the center of the gap between the motor arm and idler arm, but if you find a different position that works better for your purposes use it. The spring can also be unhooked from the tension bar so the whole upper carriage can be tilted back. Grab the spring and lift up and rearward to unhook it from the tension bar.

Center support rollers can be moved side to side for best function.

The idler arm can be moved left to tame bent shafts. Generally you will need to move the tension spring in the same direction and distance as the idler arm for best results.

The arrow stop can be moved from zero to approximately 7" away from the base carriage assembly by loosening the lock screw, sliding out the arrow stop and tightening the lock screw at the desired length.

The front pattern rest can be moved up or down as desired. Up next to the shaft for marking the pattern and cresting, or down out of the way for a clear working area. The rear pattern rest only requires a pattern taped in place.

Any of the adjustable items can be moved as you desire. There are some combinations that make the crester perform worse instead of better.
Please play with the adjustments as you see fit but be aware of the consequences of poor combinations.