Even if you have a caller you are still better off knowing it. If your competition is outdoors and the wind is blowing in the wrong direction you may not hear the caller properly.
I sit with a diagram of the arena then use my fingers to do the movements, odd I know but I can usally lean it within 5-10 mins go away then come back and polish it off etc. Good luck!
As above, draw out an accurate arena on a piece of paper, and the go through the movements with your fingers being the horse (i do diff tempos for diff paces!) until you can do the whole thing with your eyes shut, visualising every turn etc. I don't learn the markers, I just learn the patterns, e.g.,
trot down centre line, track left, across diagonal, 20m trot circle in middle of next long side, etc.
keep going through it repeatedly at every spare moment until it just flows effortlessly through your brain, like the lyrics to a song you know really well...
good luck!
I always said I couldn't learn them, and then I eventually managed to! I rode it in the arena on a horse, just in walk, and then I kind of knew the pattern. Then spent any spare time just reading it and drawing it in the air with my finger!! Also paced it out around the living room