Note:
Before you read this, I would like to mention that you cannot report someone if you don't have evidence/screenshots.

1. Once you've screenshotted the evidence, go on start menu, type %appdata%. The only file that should come up is Roaming. Click it and then press .minecraft which should be at the very top. Look towards the bottom and you will see screenshots, click it and move it to pictures.

2. Go on the forums and open up Report. Then press Server Reports which is at the very top. Then go on .net or .org whatever one the event took place. Press post thread and show the evidence.

To upload the file, look at the bottom of the text box and press upload file which should be in the middle of create thread and preview.

4. Press create thread and wait for a moderator to look at it and send it to Reports - Archives.

Hopefully this tutorial helped you if you are having trouble reporting someone.

-Diamond_Slime12