Hi there, I completely by accident stumbled across this journal. I always find it interesting when people are learning my native language and you seem to have a good grasp on it so far!

One thing, though:

Note that German uses a period instead of a colon in time expressions.

We do? I have almost never seen it with anything but a colon (see, for example, the Tagesschau clock). I am not sure where that book got that from, but I would really like to know :)