I have just got MSFS working a few days ago and have been going through the lessons. Most have been fine (although I encountered bugs in one VFR lesson and one IFR lesson) but the glider ones, well, they’re insane.
The first lesson - is it the one on basic handling of the glider ? No, that’s fourth. The first lesson is a tug plane launch, in which the tug pilot thinks he’s Tom Cruise in Top Gun. You have to stay behind him while he weaves about madly in a manner that would get any real tug pilot fired. My glider usually ends up overtaking him. I have not been able to complete this lesson at all.
The second lesson is winch launch, which is ridiculously easy. The third lesson is broken winch launch which involves having to do a traffic pattern, which would be easier IF you had had the basic handling lesson yet. It also involves dumping water ballast, something there is NO DEFAULT KEY for.
Lesson four, basic handling. Ah, it will all make sense after this, right ? Wrong. This lesson is borked. Firstly, it asks you to accelerate to 167kph, but whilst it does this it makes the altimeter constantly flash blue, to make you look at it, which renders it virtually unreadable. I resorted to external view because it wouldn’t stop flashing. So I reach 167kph and have to trim the aircraft, which I eventually manage to do as close as possible. It doesn’t seem to be able to trim perfectly, instead oscillating about ± 5kph either side but still within the tolerance for keeping the 167kph objective in the green. And the ■■■■ trim objective will not turn green. It just won’t. Eventually the glider runs out of altitude.
This sounds like you’ve experienced a lot of frustration and I feel sorry for you.
Have to say that I’m a lazy student and therefore prefer the trial and error approach.
Just like you, I’ve tried to take sim flying lessons and they showed me my shortcomings the rough way.
Overtime I picked the cherries out of the lessons and started to fly on my own.
Happy 
Just did the 1st lesson and did not experienced what you are describing, very smooth tow. Would it be possible for you to upload a video so that we can try to better help ?
Prior another intent you can assign a key on your keyboard or a joystick one:
Or you can trigger it directly from the cockpit:
My point being that if something is a necessary feature of a lesson, it should at the very least have an already defined key - defining one after the fact is too late - and the instructor should show you where that obscure control is in the cockpit. Poorly designed lesson .
Following the tug wasn’t easy, it took me 3 attempts and I had to really concentrate. Especially with the steep banking turn he does.
I also found the glider difficult to trim adequately, but I thought that was due to trimming it while in mildly turbulent air.
Yes, the flashing blue did hinder readability and was very inconvenient.
And yes, I had to go and bind the water ballast to my joystick after thinking “what on Earth is the binding for that? I’ve never used it before”.
I know this isn’t much practical help, but at least you aren’t alone 
Incoherent setup with the trim for that lesson has also been reported here:
And agree that points you mentioned could be improved for a better experience:
- ballast key setup by default and visual indication in the cockpit where the lever is located
- basic handling lesson should be the 1st one
- airspeed (not the altimeter) indicator constantly flashing blue, makes almost impossible to read the value
It is worse in FS2024!
For me at least it is impossible to launch with winch or tug plane, because the commands given in the tutorials do not work, rudder wiggling does not start anything.
The only command that sets the tug plane in motion is X when you disconnect from it!
But that also leads to failing the mission!
Any ideas or solutions?
Thank you
I didn’t dare try the glider lessons in FS2024. Now I am glad. I have gone back to FS2020 for the time being.
You did the right thing I guess 
I use the Condor glider simulation program rather than any MSFS version, but was curious to see if the flight model had been improved in 2024.
Unfortunately that is not really possible, because I cannot even take off, haha
Slewing is cheating and not an acceptable (interim) solution for me.