This will give you access to a variety of Minecraft commands, some of which I will be going over below. Open it and type your Minecraft name as it appears into the file and save it. Then, if it is not already there, create another text document called 'admins.txt' and drag it into your server folder. This will make a mod of the server first. Enter your name as it appears on Minecraft, into that document and save it. Inside the folder there will be a text document that you can open in Notepad called 'ops.txt'. Assuming that you have been following all the guides leading up to this page, you should have a folder with all the server files in it.