Complicated as they may feel they are actually very easy once you know how they work. However there are two little facts you need to know that the textbooks don’t tend to tell you.
Once you have them, you can understand all these endings and a lot more with no difficulty at all.
I hope you will enjoy this video that explains everything you need to know about n desu, no desu, na no desu and all their happy and much-simpler-than-they-seem cousins!
In the video
haha ga kuru
Is translated as “mother is coming”. I think it is clear from context but I should state that this means “mother is coming” as in “mother is coming tomorrow” or “mother is coming later today” – not “mother is (now) in the act of coming” which would be
haha ga kite iru
CF the video lesson on te-iru.
The usual meaning of “haha ga kuru” is to express either a future action or an action that takes place regularly, as in:
Mainichi haha ga kuru
Mother comes every day.