I mean, I failed both of my tests and have my third booked for soon, but I can tell you that the test is actually... pretty chill. I have severe anxiety and my palms were sweating so much on the way to the test centre that you could see it dripping on the wheel (I won't sugar coat it, it was pretty d i s g u s t i n g) and this happened both times. My heart was racing in the waiting room.
I would really, really recommend rolling your window down a little. My first examiner asked me to open hers and I accidentally opened mine instead but I acted like I intended to do it so I left it like 2cm open. Best decision I made; the oxygen flow really calmed me down to the point where five minutes into the drive, I felt like I was just driving by myself. At some points, I even forgot that my examiner was sitting right there. Most importantly though, it aired out the sweaty palms :-) Took my second test today and the first thing I did was roll my window down slightly and it worked wonders.
Even if it's a little chilly, just open it slightly. It'll help.
Second, it really goes by in a flash. I swear to god at one point, i checked the time and it was 9:10 and the next time I checked (felt like 10 minutes later) it was like 9:40 and I was so mind blown. When I'm with my instructor, the hours drag, but trust me, your test will be over in the blink of an eye.
Aside from that, it's all really just basic stuff that you do with your instructor. If you can do what you did with your instructor, no problem at all. Good luck!