You always have to squeeze the clutch in to install a belt.
When it fits properly the belt will be 1-2mm below the top of the clutch pulley, and wrapped snugly around the crankshaft.
The best way to verify it is all working right is to draw a few lines on the face of the variator with a Sharpie or other Magic marker. When you ride the bike for a mile or so the marker will wear off, and you can see exactly how far the belt is traveling.
It should erase the lines to within 1-2mm off the top of the variator.
That shows you everything is opening the way it should, and the belt is the correct length.