Beginner - what to do in my first few sessions?

I vote for having fun.

I vote for technique so you don’t develop bad habits. Good technique will prevent you from plateauing quickly which would not be fun. 

+1 to just have fun. In many sports, but especially climbing, it's easy to fall into a type of hyper-performance mindset ("what's the best way to get better? Am I maximizing my learnings?"). You have a lifetime to improve your climbing. Whatever grade you managed to climb in your first year or not will most likely bare no correlation whatsoever to the grade you'll climb in your 10th.

That being said, I think the main mistake I made when I started what to hangdog way too much on things that were just way too hard for me at the time. In your first few years, I really see little points in trying the same move 50 times without ever sticking it, or to work on routes/problems that realistically you have no chances of sending that year. Most stuff you get on, you don't have to send, but your should at least see how you COULD send it. Or you could fail to send because of endurance/pump, not because you're unable to do the single moves. I got injured a few times (pulleys, biceps) a few times doing that. You SHOULD fall on stuff. But just not on desperately hard stuff.

The other thing I would advise is aim for broadness. Get on steep stuff, get on slabs. Get on crimpy stuff, get on slopes, jugs. Try as many different styles of routes you can. This will allow you to build a broad base of technics and understand of climbing in general. Once you have that dialed, you'll have a good base on which to get on harder stuff, projects things that feel hopeless, etc. if you want.

EDIT: you might also want to give downclimbinb the easier problems a try. I only started doing that after many years of climbing, but I found that the dynamic is different and complementary to that of climbing. I feel like I understand my mouvements, and I am better able to predict the effect of dynamic moves (transfert of weight etc) after some time practicing downclimbing. Some say it may be good for injury prevention as well (since you're essentially doing excentic movements & working antagonistic muscles).

I'd say obsess over 7 million youtube videos until your next sesh.

Lots of mileage on stuff you can actually climb. Concentrate on doing them the easiest way possible.  Not only will this improve your technique, but it will allow your tendons to strengthen without your getting injured.  Muscles gain strength much faster than tendons; this can lead to big problems for new climbers.

Auden Alsop wrote:

https://www.mountainproject.com/forum/topic/120298921/beginner-what-to-do-in-my-first-few-sessions

Is this spam? It being a repost and having a random suspect link in the middle of the text?

This is truly bizarre. Are these posts AI generated? If so, it’s impressive.

Climbing friend,

You must avoid wasting time with the climbing at all cost, and instead you would only train footless exercisings such as the power campus, in order promote fine incredible growth of your firearm musculars, impressing on everyone with your feats of strength!