Thank you for coming here and asking, its a very sensible move and I'm sure will make you feel more comfortable and that yer hesitancy is not peculiar to you, many have had it -and overcome it in the end.
I think you have been given some pretty good suggestions, practical tips on what to do - all good.
In all those words the one you may not have picked up on is patience.
It takes patience both by you and the passenger/instructor.
You anticipate when you get in the driver's seat you will react, a full blown panic attach or maybe just a lesser one. So make that your plan for that session, let yourself have the reaction, then when it lessens tme to end the session.
The next time see if you can plan to do anything at all after the attack, even if it is only touching each of hte controls in turn. That is a victory, you have got past the first hurdle.
The third time ... well you get the idea.
You have two things to contend with , acquiring the skills in driving the vehicle -and you have had good advice on starting in an area without obstructions, and taking it from there.
The other and really harder thing is to cope with your own reactions. Now on that one I would imagine you might have some ideas, maybe taken form other times when you have controlled panic attacks, or discarded feelings of not being good enough.
Would you like to make suggestions on this?