Hi -- I have a GW670III... polarizers are a bit weird to use on an RF camera. Probably the easiest way is to hold the filter in your fingers and look through it toward the scene and rotate it until you get the effect you want. Note carefully its orientation, and then put it on the lens and rotate the filter to the same orientation. A few degrees + or - won't make a lot of difference.
There are various mechanical marvels of engineering to get around this awkwardness. For instance, one product is composed of two polarizers geared together so the orientation is the same for both. You look through one and rotate it as desired, while the one in front of the lens rotates to match.
Another gizmo has the polarizer on a swing-out mount so that it flips out away from the lens 180 degrees... you look through and rotate the filter as desired, flip it back in front of the lens, and there y'are. Tricky...