Translation:I am coming up from the basement and going up into the attic.
It's really exhausting to try to learn when the course still hasn't been even minimally proofread by an English speaker.
Indeed. Maybe you can suggest it to the course creators, maybe they will hear your voice.
You can try directly communicating with them. This is a link from the Help:
I've posted on the discussion list many times. I even tried to volunteer to do it, but was stopped by a stipulation that one has to be fluent in both languages -- laughable in this context.
Well, if nothing else works, you can still report all the issues you find via 'Report a problem', that goes directly to the contributors, and you can add all your suggestions there. Good luck!