There are 2 ways to use a root level domain for your contest.
Method #1 - Using an Embedded Form
This only works on pro plan or higher.
In this method, you'll host your own landing page, so your domain should already be set-up. You would already have your own hosting, for example, for this to work, and your DNS would already be set-up prior.
For this method, you need to see how to use the embedded form.
Note that embedded forms will still show a thank you page hosted on VYPER. In order to get your thank you page or leaderboard page to show up on your domain, you need to set-up a subdomain and be on the Enterprise plan.
Method #2 - Setting up a Root Domain
Important to note that for this to work, your domain must NOT already be used. So for example, if your site is already at https://vyper.io, using this method would override https://vyper.io with a contest.
Step 1: Navigate to https://vyper.io/subdomains/create
(You must be on Enterprise level or higher).
Input the root domain with www. before it. (For example, your domain MUST be www.vyper.io instead of vyper.io)
Step 3: Set-up a cname record in your registrar for www. pointing to vc.vyper.io
Here's an example at Godaddy.
Step 4: Set-up forwarding
Forward your non-www URL to the www URL.
Here's an example of how to do it at Godaddy. The following setting assuming the domain you're trying to do this on is vyper.io