I'm only a novice myself, so perhaps someone can correct me, but I believe you move past tab 2 simply by selecting the next tab, assuming some assignments have been uploaded. Unlike Assignment, I believe Workshop requires a file to be uploaded, even if it's just a brief description (or identifier) of an off-line activity. Note that students cannot upload anything until after completing their reviews of teacher examples if that is set > 0.
The Workshop interface to the student is similar to uploaded Assignment: a box for browsing a file with a button for uploading. Try logging in as a student (add a dummy student if you like) and have a look.
Also, the Workshop interface has been subtantially modified in 1.5, so that you set begin and end dates for submissions and assessments, rather than selecting tabs.
Hope your workshop works out OK.