To leave the discord server, you click the three dots on the top of the server when you are not inside of a channel like this. After you click those dots, you go down to the bottom of the tab that pops up and you should see something that says "Leave Server", Just click that. If you have any difficulties doing so, I will be more than happy to help some more.
#trying to leave
formal moss
dull kindle
Just git gud 
But in reality do what the person above me said ^