Thank you, glad you enjoyed it! I'll definitely have to write up some external instructions for the junctions. The level that introduced them went through several iterations with us trying to make them easier to understand, sucks that they seem to be such a confusing point so early on...
Basically a junction allows you to control the direction of a conveyor during play mode. The direction of the conveyor will swap between the two directions the the blue arrows point. When you place a junction, the blue arrows point towards the original direction of the conveyor, and the direction you select with the purple arrow. If you press the place button multiple times, it changes the DPAD direction that controls the conveyor belt during play mode.
So once in play mode, check the lil DPAD icon on the junction, and press that direction to toggle the junction!