Congratulations! I knew you'd be just fine.
As for muscles, I liked to pretend I was working out to learn the muscles. Flex your arms. What is flexing, what is relaxing? Now squat. What is flexing, what is stabilizing? Now stand up. What muscles are helping with extension? Turn your head to the left. What muscles are working now? And so on and so forth. I'm a hands on learner, so that helped me immensely... Also, if you work out, you might know some of the larger muscles already.
That's just me, your mileage may vary.