What do you press to use the scope on the snipers?

Right click

U go to secondary fire in settings and click the button you want to aim

Like what Tyler Schimidt said, you go in settings, controls then find secondary fire and it tells you. If you hav'nt ever changed the settings, it should be the right mouse button and to do that, tap the mouse[pad] with TWO fingers together.

Hi click right button you need a mouse that you can left and right click at the same time

Right click and you will see through the scope but you can't left click with the right one down on MacBooks, so when you are right clicking just tap over the trackpad to shoot

To use the scope on most guns and almost all snipers all you need to do is press down the right click mouse button, you can then use the mouse scroll wheel to zoom in and out. Snipers without scopes like the snap shot and the particle lance can still use a zoom but it is still more of a zoom than a scope

Just right click