I know what you mean, Susan! I avoided the publications for the first few months I was on Medium because of the different submission rules, and I was unsure about the difference between just submitting a story and being a writer for a publication. So confusing! I was fortunate that Fit For You approached me about being a writer and as I wrote more articles for that publication, others noticed me and I was either recruited or I asked to be a writer. I still don’t have a large publication portfolio but I write for ones I really enjoy. They are more than enough with my busy schedule but I am open to writing for others if the opportunity presents.
Give it a try. Submit and see what happens. Like I said, alto loves dog stories for Crossin(G)enres and he is a pleasure to work with. He will answer your questions and help. I will too if I can.