I would check with your professor.
Usually a "make up" class is an extra day that you will use if a normally scheduled class is missed (a normally scheduled class gets cancelled or you are too sick to go to class one day). But if you go to every class, you don't need the make up class.
This program has scheduled the make up class for January 20 as a default. However, if your professor wants to have the make up for some other day, she/he can schedule it for wherever.
So, I would assume you *don't* have class on 1/20, unless you miss a class. If you miss a class, you *do* have a class on 1/20, unless your professor tells you otherwise.
But I'd ask to make sure.