Hello! I hope you enjoy it here and welcome to Ribblr 
to answer your questions, to follow a shop when on a shop click the heart that’s by their shop name, which is above them. Yes you can get free patterns (Limit of 5 free patterns every 24 hours, the 24 hours start when you get the pattern) some free patterns will say followers only with those patterns you must follow (Heart) the shop to get the pattern.
By selling what do you mean to sell? Patterns or makes?
Here’s something I try to do when I can for newcomers if you ever need help never hesitate to ask in the community, if you need immediate answers feel free to use the help center, search in the community, or the wiki [link below] testing guidelines and community guidelines if needed Happy crafting! Congrats on your first post and hope to see your crafts soon as well