By default, most of the "advanced" features are hidden in COMSOL. This includes the equations that it's actually solving, plus a lot of other useful things like selecting the order and type of the finite element. The details vary depending on the version of COMSOL (you mention your version but I don't have that in front of me at the moment!).
Go into Preferences and find the preferences page that lists a whole bunch of (by default empty) check boxes selecting whether certain things are visible.
The first thing I do when I install a new copy of COMSOL is check all of those boxes! They're trying to keep the user interface uncluttered by default, but I think they overdid it by hiding some really important features.
There's also an entire section in the documentation on equation-based modeling, but that's generally done when you're starting from scratch and not using some of the pre-defined physics modes. Still, it's worth reading it in order to understand what the software is really doing.