Where can I upload videos? https://www.youtube.com/
Generally evidence should not be older than two weeks at time of submission.
We understand that sometimes when you come here you're angry, you want to get back to your game, or something happened just as you had to leave. But the format is important! It gives us much of the information we need to quickly address your particular problem.
Also keep in mind that evidence is VERY important when posting a report, we can't just ban, jail, or mute a player every time someone says they did something wrong. How would you feel if someone pointed you out because you did something they didn't like and we jailed you just because they asked us to? Even though you didn't do anything wrong!
So get those screen shots, fill out report and provide as much information as you can.