This is generally a nice kit, but there are some serious errors in the Circuit guides.
Specifically, the wiring diagrams for #10 (dc motor) and #11 (relays) are incorrect. These are the two sketches that use a transistor to switch power to the other components. Both also incorporate a flyback diode across the motor or relay coil. The symptom in both cases was that transistor didn't appear to work, ie. the motor would never spin and the relay would always remain in the NO connection.
The schematics for both are correct, but the wiring diagram gets the emitter/collector for transistor backward. The transistor pin in 4a is the emitter and should be connected to GND. The pin in 2a is the collector. The wiring in both diagrams is the opposite of this. The transistor in my kit is marked MPS 2222A, and I saw a post indicating that there is a similar, less common, transistor that does reverse the collector and emitter pins. Perhaps that was used in some other kits and would explain this mistake. Check what is in your kit.
In addition, in #11 the polarity of the flyback diode is incorrect. The black band should be in 7f connected to 5v, not in 7e.
I've gathered this info from various other posts and datasheets, but I wanted to collect it all in one place with a clear subject to save someone else some time and grief.