After you log into your Wix site, the first page you’ll see is the Wix dashboard where your Sites will be. Find the Help tab

Wix Dashboard: Where is the Help button?

From here, you’ll want to use the search box to find what you need to succeed

Shortcuts to helpful Wix pages:

https://support.wix.com/en/article/assigning-an-unassigned-premium-plan-to-your-site