If you are new to the reformer this is probably not the best place to start Claudia - you should check out beginner level reformer workouts on the website. better for you. The springs change exercise to exercise and it also depends on the type of machine you use and your personal size, weight and experience - so there are always many factors to take into consideration. Do watch some basic trainings and if you can work with someone that is your best place to start.
A bit unusual to not mention what tension for each spring, at least as a general guide. There's a huge difference between one green and one yellow, e.g.. Also she forgot to do the thigh stretch on the other leg at the end! However, I learned a lot from this video, one of the ones that it's helpful to really watch her giving physical cues and corrections and then rewinding and trying it yourself.
Kari H Thank you for your comment. Regarding spring color and tension - this was a Gratz reformer, so only four springs and they are all the same tension.
I re watched the class and had a smile - you are right, I did not give thigh stretch on the second side - thanks for pointing this out. Enjoy....