I want to use Waze to follow the route created in Routexl
You can use Waze to navigate to each stop individually. Either by selecting a location and use the Navigate button, or by opening the Download > Fulfill dialog. Both require that you select Waze at Options > Routing > Navigate with.
Exporting the full route with all stops to Waze is not possible yet, only because Waze does not accept multiple stops at this moment.
I have tried to use navigate with and select Waze as the program. But when I select a location and navigate it opens in Google Maps not Waze??