Armortek

Hi all,
Can anyone out there tell me how to set up an old DX7 transmitter for right stick only driving. I am definitely not a whizz with electrics or tech speak so I am afraid it is best to treat me as a complete duffer as far as this is concerned.
My grateful thanks will go to anyone who could help.
Kevin.

Thanks to Mark from Armortek for the info. Unfortunately my DX7 does not have a roller so must be very old now . I guess I will have to invest in a new one sooner rather than later.
Thanks again.
Kevin.