I'd like to get started

I’m having trouble getting started.

At the top of the dashboard, it says “Start Selling”, I click on it, and I go through a loop.
I have a specialty in designing 3D objects, I can also make music too. If I can, I prefer not to stick to just one. But if I have to, it’s 3D objects.
I can’t seem to be able to contact anybody. Just through the forums.
I’m currently working part time at a non computer related job. But I would like to eventually like to be making 3D objects and selling them online, eventually full time but don’t have time yet.
-I’ll probably end up spending time getting feedback on my 3D objects, promoting and fixing them. Working the full time.
-I’ve made a few sales on other sites, not many though. I have a few products on other sites. Eventually I’d like to sell them here exclusively if it works out. Would I have to shut down my accounts with other sites to sell them here to get a higher percentage?
And is this the right forum?

How do I get started with this?

You are an exclsuive author at the moment - you cannot sell the same items elsewhere at the same time.

Either you need to be non-exclsuive and earn lower % OR be exclsuive and remove them from other marketplaces