I'm a newbie with this ACOG and with it mounted on my AR-15 carry handle I'm uncertain where to start relative to sighting it in. What am I supposed to align the dot with? The end of the barrel sight? The ACOG Dot is far too high for that, and that's with it adjusted all the way down. So far, I've not been able to find any tutorial videos that offer entry level instruction for the beginner. I'm an experienced shooter, I'm just new to using scopes. Any help is greatly appreciated.