How do I sign a contract with tapas?
As a pitch to be premium or a regular creator on their site?
There are two different ways. I believe Premium might have something in it's language that lends itself to whatever work you're pitching them will be exclusive.
Okay so how do I signed...?
A contract for what?
As a regular creator, you just create an account as "Publish."
Click that and then "Get Started". It's the same as any account on say DeviantART.
I believe you need to be offered a contract to be exclusive to any site (including Tapas or Webtoons). For now, you can just publish on the site as an independent creator (non-exclusive in this case)
Probably you mean this?
If you just wanna publish your comic or novel you don't need to sign any contract.