Didn't realize Sun Country expected me to memorize ALL of these airport codes prior to training. Training starts in 3 days. Any advice?

I didn't realize I needed to memorize airport codes prior to training. I'm going over all of the stuff they sent me on the 23rd, now that I'm packing and prepping now that Christmas and my birthday are over, and I'm discovering that they expect me to memorize all of these airport codes. This list is huge, and trying to memorize all of this in just 3 days is craziness. Even if I were to try and memorize them since the 23rd, it still seems difficult. Does anyone have any advice or insight on how these tests work and what I can do to prep myself in time?