Watch the Mixolydian Scales online guitar lesson by Bruce Arnold from Jazz Guitar for Beginners
When applying a Mixolydian scale to a II V I keep in mind that you would only think the Mixolydian scale if in fact the V chord was being played long enough so that you heard the V chord as the key center.
Although I've set up a jam track that does make the V chord a key center it usually takes a few measures before the ear settles into the V as a key center.
Again I mostly want you to realize that you cant learn music without using your ear, and knowing what key center you are hearing in will make you a much more musical person.
You should learn your Mixolydian scale in all keys because II V Is can be found in all keys when playing jazz. The PDF will g I've you the fingerings for the Mixolydian scale.