If for whatever reason, you don’t want to use Alexa helper, there is a very simple smartapp in the “marketplace” section of the official mobile app which only does one thing: assign a mode to a switch.
To find that one open the mobile app, select the marketplace section (use the*icon at the bottom of the screen), choose “smart apps”, choose “lights and switches” and you will find it. 
Click on it and complete the set up wizard. You can do one switch changing to one mode.
Now you have a switch that will activate that mode.
You will have to repeat this installation for each virtual switch that you have.
( One of the big advantages of Alexa helper is that it will let you do multiple switches in one set up wizard. But this way should still work. )