Polar alignment of your equatorial mount can be done in several ways. The easiest way is to use your latitude.
The polar axis of an equatorially mounted scope must point at or be polar-aligned to the north celestial pole, the point in the sky around which all the other stars appear to rotate. The pole is directly above the north point on the horizon. So your axis must point both north and also be tilted up at an angle. Since the altitude of the north celestial pole is always equal to your latitude on the earth, you can just use the scope’s latitude adjustment to raise the polar axis to the right angle.
For the Omni CG-4 mount, the scale ranges from 0 to 90 degrees. The true range of adjustment is roughly 20-55 degrees due to the counterweights and head castings.
Either look on a map, use Google Earth or an almanac to find your observing site’s latitude. Unlock the latitude adjustment screws on the sides of the mount and turn the latitude adjustment screws until the index on the polar axis reads your latitude. Tighten the adjustment screws if needed to secure the latitude setting. (You may also need to loosen the center pivot bolt by turning the hex nut to allow the equatorial mount head to be tilted.)
Now complete the polar alignment by turning the entire mount (not either axis – both should be clamped tightly) to align the upwards end of the polar axis with north on the horizon. If doing this at night, north is located directly below Polaris, the Pole Star.