Free hosting plans do not support the Site builder, you can still build a fantastic site using any site builder software on your PC and upload it to the server,
Here are some open source site builders you can use
or install a great site using Softaculious in your cPanel here.

To get the extra functionality of the Site builder please order a premium hosting plan:
Order new premium account

Or you can upgrade your entire free hosting account to premium using our upgrade process here:
Upgrade existing account