If you are making your tour for mobile, enabling mobile optimization can make your tour better suited to a mobile experience. If you have no plans for mobile, you can disable it.

1. Enter the edit mode to the tour you want to enable mobile optimization

2. Select the ‘cog’ symbol to enter the tour settings

3. Near the bottom you should see the switch for enabling ‘Mobile Optimization’

4. Click on the switch and click 'Update'

Your Tour is now optimized for mobile.