I do it the way Delete said. ;)
Once the horse's right shoulder goes forward, I rise. :)
You'll get it; it will take some practice on everything since you haven't ridden, but you will get the hang of it soon enough!
have fun in your new job . dont worry to much about postion it will come when you have lessons, and it is generally a few little things to work on until you get your position back. just think at least your not starting from the beggining and have never ridden before you at least have the baseline good luck