For novices the first couple of locks can be a bit challenging. The boats are not reacting so quickly as one would like, so bringing the boat in parallel to the lock walls is one task, and handling the ropes over the bollard and keeping them tight the other.
After some more or less embarrassing trials at the first locks we found our rhythm and only occassionaly had problems afterwards, e.g. when the wind was affecting the boat. Neverthess in those moments it quickly became four captains as everyone knows better how to handle the situation.
Fortunately, having four people on the boat makes the whole thing much easier. One person gets out before the lock and walks over to help from outside with the ropes and the bollards, two persons take care of the back and front ropes to keep the boat stable during the locking and one persons steers the boat entering and leaving the lock.
With only two people, the whole thing obviously becomes much more challenging and the interesting part of the trip was actually watching some couples completely loosing their contenance, insulting each other with words I can't write here. So beware, what might look like a romantic, relaxing trip can become your last together or maybe the ultimate proof that you can handle everything together. So better do the trip before your marriage ;-)
Btw, although a bit tricky for two, the good thing is that there is generally a quick supporting hand around and the chance you damage something is pretty low.