Welcome to the cookie community. It was so long ago that I started decorated cookies there weren’t online classes. My first class was at Michaels because my daughter was interested. She lost interest, but I didn’t. I learned a lot about how to make cookies and we worked in buttercream. There weren’t many cookie decorating classes so I went and took Michaels cake classes. Cakes were never right for me and I started doing cookies with friends' advice and Karen’s Cookies. Karen is Karen of Karen and Mike summers who do CookieCon. Their website is gone, but CookieCon has made cookie decorating big business. To answer your question, I would work in the little things like how to make rolled out cookies, how to make royal icing, and how to hold a piping bag. If I was you, I would look into Bearfoot Baker. Lisa has been doing it a long time and is geared towards basics. Lisa is very friendly and is happy to help beginners. Once you get the basics, you find a few cookiers you like (like Julia) and imitate their work until you find the style you enjoy. Good luck.