Conglatulations on your lesson!
I prefer group lessons, more people to help and support you when your stuck and plus make friends and learn from eachothers mistakes/strengths. I've been in a group lesson since I came off the lunge (about 6 years ago
) I love the support you get!
Anyway as with rising trot, its one of them things that you either get striaght away or dont. Luckily once you do understand it stick with you and you can improve tremendously (I now dont even have to look down to see if I'm on the right diagonal
Basically its just practise, practise, practise to get rising trot. I remeber all those years ago when I first learnt rising trot that counting in my head was a great benifit. Just going steadily 1-2-1-2 in your head or out loud to tell you when to rise and sit might help.
Or you could look at the outside foreleg of your ride and try and rise when it goes forward and sit when it comes back, eventually you will find the rhythm!
Good luck with your lessons as you progress!
Hope I've helped