you need to ensure the boiler is primed. you dont need to wait (and i wouldnt wait)
1. fill water tank at back /front / ??
2. open steam wand put jug under it
3. turn on machine
4. run either water switch or "brew switch" until a steady stream of water runs out the steam wand.
5. close steam wand (and water should pour out Grouphead if used brew switch, not sure if using water switch and if the VV has one)
5.5 turn off water / brew switch
6. wait to heats up
7. make coffee........
#fill boiler again after steaming any milk please!!!
i used to do the "fill boiler routine" when i turned it on and when i was turning it off.... this way you have double the chances of making sure your boiler is full...... it also gives the group head a nice "cleaning" flush every day....
Just get into a routine that suits your style....easy
IMO I would not leave it on all day........
and welcome to CS