This is the unfettered truth:
You don't need anyone's permission and you don't need to do anything specific to post to the mainsite other than, you know, actually posting to the main site.
This is the truth in context:
Post a draft, get feedback. Read that feedback, parse it, let it sink in. Edit your draft, and get some more feedback. Repeat at least until one or more experienced authors tell you it's good to go, or at the very least that it stands a chance. If someone tells you it's great, check if they have an author page, and see how many articles they've written and what their ratings are. Weigh their opinion on that basis. Also, if you use dog shit to make chocolate mousse, no matter how much you pretty it up on the plate (i.e. add test logs, add more backstory), it's always going to remain dog shit. When people tell you the core concept is unworkable, you don't have to suck it up without questioning their opinion, but you do need to seriously think about what you're doing.