Its all a matter of weight distribution and balance.
If you imagine the pad rotating in a clockwise direction ........
if you lean the machine forward its going to go to the right,
if you lean the machine backwards it going to go to the left.
Get it balanced and you go no where.
but you want to go somewhere - do you want to left ? - what do you need to do.
do you want to go right ? - what are you going to do?
Once you got the knack - its like riding a bike - you never forget.