After you've deployed your site to Netlify, you'll want your custom domain to point to the Netlify site, not the Webflow one. You may do this in the Netlify dashboard.

1. In the Netlify dashboard for your new site, click on "Site settings"
2. Click on "Domain management" on the menu on the left
3. Click the "Add domain alias" button and input your Domain name

For more information on Netlify and custom domains, see the Netlify documentation.