Crossfit’s workouts can include powerlifting; gymnastics and calisthenic type activities like ring pull-ups and rope climbing; and often cardio in the form of running, cycling, or rowing. You can also expect stretches, push-ups, and a lot of other stuff.

A class will be centered around&...

You can get a training session before starting classes. This will depend on your gym (your box) but some offer a free session to teach the techniques.

Boxes also let you sign up for a series of beginner-specific classes before you jump in with everybody else.

Bars come in a variety of weights, from 15 to 45 pounds, and those giant plates are available in sizes going down to 10 pounds. 

That means the barbell has about the same shape and size no matter how heavy it is.

Nobody expects you to Rx a workout anytime soon. Even at a box full of experienced athletes, very few people are doing the prescribed (Rx) weights or moves every time.

Those numbers are a goal to work up to.