Been fucking sectioned, said section 2 whatever that means, how can they legally stop me from doing what I need to do, could be in here for 28 days, but there’s ppl in here that say they’ve been here for months!
how do I get them to let me leave?
Yeah, it's absolutely scary when you connect the dots and realize how quickly your due process just vanishes. Having been there, my advice is similar to the other posters' so far. They will likely offer "optional" group therapy / activities / free socialization time / whatever. You won't feel like doing any of them because many of the structured activities are condescending and degrading, and despite your illness you have some self respect and pride.
Unfortunately, the game is that the more you do of those the faster you'll get out. Don't act like you improved overnight, just be consistent and regurgitate all their nonsense back to them, reassure them when they go through the self harm questionnaire, volunteer to answer questions when they ask them in group and keep your head down and don't make waves.
The highlight of my time in the ward was when they brought in a washed up counselor in with two fresh faced apprentices in tow. I was sitting quite near them, and before the session started he was telling them how much he hated these presentations and that they could just wing it and nobody would know any different. He then proceeded to lecture us for 20 minutes on the importance of sleep. Okay, great. Then the ward placed us in a room with a dude who woke up every 45 minutes and loudly asked the entire room what day it was. Over and over and over. Zero sleep that night. A fellow inmate and I both complained about this, so they moved us to a second room. That room had an addict who was in the process of detoxing, who again kept us up all night.
After I was released I received an enormous direct bill from the ward's doctor, which at the time was against the law in my state. He saw me twice for 15 minutes each and did absolutely nothing other than sign my release. In short, you'll get to see how much of a joke the mental health services are in your country, but play the game and they will eventually cut you loose. Best wishes for an early release.