One of the technique to aid us in our path of spiritual cultivation is to learn to rejoice in our own little progress each time.
Instead of aspiring to learn fast or learn many things in a short time, we should learn to accumulate our joyous perseverance each time, as this will ensure that we last long on this path.
How do you then accumulate your joyous perseverance when you are learning something that you do not understand?
The key concept is in mastering the art of looking for the little progress each time on your own path of cultivation via continuous reflections. Even if you completely do not understand what you have just learnt, you can reflect upon whether you managed to endure a longer time before losing focus.
This has to be practiced continuously, after each lessons, and also at the end of the day to reflect upon the progress made daily. Importantly affirm yourself of the progress and build up that joyous perseverance spirit to recharge yourself.