Where-ever the marshaller is standing, in whatever direction to you, imagine he/she is directly facing you, (face on) and each of his/her hands controls a wheel on your aircraft directly ahead of it. (ie: his/her right hand will control your left wheel as he/she is facing you). So the stationary right hand freezes your LEFT wheel and his moving left hand/arm makes your right wheel continue to move. So your aircraft turns left. This signal applies WHERE-EVER he/she is actually standing in relation to your aircraft (the marshaller could be to one side, over your left shoulder, etc etc)- you have to transpose him or her to directly in front of you, facing you, and then let the hand movements control the wheels they "face".
It'svery annoying at some of these fly-ins where amateur marshallers are allowed to stand around and THEY don't know how to marshall! The usual mistake is that they wave both hands towards themselves even when you are taxi-ing past them at 90 degrees, and they think they are saying 'turn towards ME' when in fact the signals they are making are saying 'continue straight on across me'. When you get past them, they start getting frustrated and annoyred and all sorts of signals start