Help with grading

I am very new to using Desmos. I spent the weekend creating a small activity. I would like to use slide 13 to grade and give students percentages on how they did. Slide 13 is not mine I borrowed if from [Copy of] Topic 2 Test • Activity Builder by Desmos

I was also playing with slide 12 which I borrowed from a co-worker.

Here is my activity. Rotations Review • Activity Builder by Desmos

any assistance would be greatly appreciated on how to alter the coding to fit for my activity.