Enable Install Complete Dialog:
If enabled a custom OK Dialog will appear at the end of the install process. This can be a useful opportunity to let the user know they can start using their device. These dialogs are standard Kodi OK Dialogs and so you really want to keep these as short as possible as you can only squeeze in a max. of 4 lines of text. You can set this option in:
Loading Screens -> Click here to customise the Install Complete dialog -> Enable Install Complete Dialog
Just below this there are text fields where you can set the header/title of this dialog as well as the main text.
Although it's rare you may encounter a device which doesn't play nicely when trying to reload the Kodi profile, by default this is performed once the install is complete so the device doesn't require a reboot.
In the unlikely event you do encounter problems with the install you can choose to have the system reboot once install is complete. You would generally only need to set this if the 3rd loading screen gets stuck at 100% and you can't get past the update screen. To enable/disable the reboot option you'll find it here:
Loading Screens -> Click here to customise the Install Complete dialog -> Reboot on completion
A full guide to the Startup Wizard configuration: