To assign a Hosting plan to your domain registered in SW Panel, go to the tab Domains and SSL -> Domain portfolio that you will find in the left side blue menu:
Then find your domain and put your mouse cursor on the menu [...].
💡 If you have more than one domain, you can easily find them using the search engine in this section.
Click on the option "Create a service to this Domain".
In the example, we will proceed to deploy a Smart Hosting Free v.2. Click on "Hosting Plans".
Select the Hosting service in question.
💡 If you wish, at this very moment, you can create an email account, modify the PHP version of your Hosting and deploy a CMS. If you don't want to do it now, don't worry, you can create it later.
Go to the bottom of the page to formalize and create the Hosting service.
You are done! You already have your domain associated to a new hosting service.