After 3 days you’ve already had your first LD…darn you lucky bastard!
About your question. Just like you’ve learned yourself to do a RC when you encounter certain dream signs, you will also have to teach your self to take the next steps in lucid dreaming, which is taking control, stabilizing and prolonging the dream. There’s a good topic about this in the FAQ & Tutorial section:
https://community.ld4all.com/t/prolonging-lucid-dreams/24077