Tuner question

I bought my tuner for my 2020 Edge ST. I sold it and removed the tune. I replaced it with a 2011 Mustang GT. How or can I use the tuner to load a tune on my mustang? Do I need to buy another credit or?
Used to the SCT tuner with only one tune one vehicle so need some schooling.
Thanks

You just have to buy more credits. Once you've used the credits on a vehicle they're gone, but you can just buy more for the new one.

Are you using SCT or HPT? If HPT you just need to read the new vehicle and get the needed credits to tune the new vehicle.