What you want to do is not possible on the GoCentral web builder application at this time. GD is adding new features pretty regularly which you an follow on the GD GoCentral Blog page. 😉
Not having this feature makes Go Daddy practically unusable. It is THE template begin page I have used in the past and prefer to use NOW. Nit when Go Daddy finally gets up to Wix or any of the other competitors. Not having this feature makes me contemplate dropping Go Daddy as usable. I thought such a feature was required in today’s internet market. It actually is! Shame on Go Daddy fir such a **bleep** unworkable approach. My tenure here will be brief at this rate!
GoCentral is not your only option... Maybe a web builder, which by it's very nature is limiting, is not for you? If you want the control you seek, check out WordPress. Layouts, themes and plugins so that you can accomplish exactly what you want. 😉