Check out the below Suction Cup Mount tutorial videos for complete mounting instructions. There are two tutorials here - the first is for the new Suction Cup Mount, and the second is for the old Suction Cup Mount. You can tell the difference between the old and new Suction Cup Mounts by how you lock the them in place. With the new mount, you rotate the lever down so that it's in a horizontal position to lock it in place. The old mount requires you to rotate the lever up so that its in a vertical position to lock the it in place.
This video is for the new Suction Cup mount. Notice how the lever is horizontal once the mount is locked into place.
This video is for the original Suction Cup Mount. Notice how the lever is in the vertical position once the mount is locked into place. We no longer sell this version of the Suction Cup Mount, but check it out if it looks like the version you have.