We can't switch the initially chosen template at the moment but that feature will be coming soon!
You can change the menu style of your app under Build -> Navigation Menu -> Layout
Choose between 'Drawer Menu' with a top bar navigation and slide out menu or 'Bottom Tabs' where users can access tabs and then a pop out for additional menu items.

You can change all aspects of your app by adding and removing Pages and Components and changing the Design settings in the Build section
You can preview templates below:
ICE
FRANKFURTER
CAFE
EVENT
RETAIL
MAINTENANCE SERVICES
PUB/BAR
SALON
RELIGIOUS ORGANIZATION
WEDDING
EDUCATIONAL
HEALTH & FITNESS
REAL-ESTATE
ENTERTAINER/ARTIST
SPORTSCLUB/TEAM
CHARITY
AGENCY/CONSULTING
ONLINE TRAINING PROGRAM
REOPENING - PUB/RESTAURANT
If you really want to select a new template you can always sign up again with another email address for a new account. Alternatively we can reset your app to a chosen template.
Below is a link to an example Beezer app:
We hope that helps