I remember talking with my doctor (not my AME), he said getting his instrument rating was as mentally challenging as a semester of med school.

I'm not sure how Gleim does it, a paragraph about the subject and then the questions that cover that idea? I know they say they require the least amount of study and just cover what you need to know for the test. Think about this, this is your life. Granted, I can count the number for for real NDB approached I've shot in 30+ years without taking my shoes off but you need to understand the basics so later you know what the gee whiz magic is doing. Otherwise you're just a trained monkey.

Ok, sorry for the rant. Draw it out. Plane is here, wind is from here, NDB and airport. Wind is going to push me, needle is going to keep pointing to the NDB, I need to turn this way. Pay an instructor for half an hour with a chalk board. There are all sorts of sayings about turning towards (and past) the head of the needle going toward the station and away from (pulling) the needle going away from the station but you need to be able to visualize what's happening.

I still draw holding patterns. Humans are very visual creatures. You have to be able to "see" what's happening even if you're IFR.