Susie, I realized I missed a step. When you have completed your piece and click on the 3 lines in the upper right of the screen, you have to choose Submit to Publication. Then, a list of publications for which you are a writer — and from what you wrote I assume that will only be Weeds & Wildflowers — click Weeds & Wildflowers and then click Select & Continue on the lower left. Then, choose your tags. Then, click Submit to Publication.
Sorry, I was tired last night and made the mistake of doing a sample post for my own publication. When it’s your own publication, the choices are different.
Anyway, I hope this isn’t too confusing!