New to this

So i decided to start my online store that ive been dreaming of for a few years! Im completely confused but the videos and stuff are helping a bit! I only started this store because i was on Shrooms & it boosted my confidence to get it done! When i got my first order, it came with high fraud warning! I cancelled it because i did not want to deal with that so soon into opening, I haven’t had another order since. What can i do to improve!?