Select Virtual Tours -> Editor UI, from side menu.

Here you can see all the elements currently visible in your tour and modify them.
 

Click on any of UI elements to edit them; you can enable/disable their visibility and change their apperance.

On top of the edit menu you can select to modify environmental elements like:

• Font, Change the general font of the whole tour
   
• Main Form, Set the parameters of the general form
   
• Default Markers Style, Set the style parameters of the new Markers
   
• Default POIs Style, Set the style parameters of the new POIs
   
• Presets, Save and load UI presets
   
• Tooltips, View or not the tooltips of the elements when hovering them

After changing the UI click Save in top right corner of the page.