How to i ban players on my minecraft server?

I have a server that i bought from gameservers.com and it came with McMyAdmin 2 and every once in a while a very bad person that hacked my server IP joins and does the best in his / her ability to destroy our stuff (we play on survival). I might be a major noob for this but i don't know how to ban players on it. What i really need to know is how do i make my Minecraft account an admin so can type in the commands to ban people. This will Really help with getting this guy to go away.

If you are the owner, do /ban.
If that does not work, do /op [yourname] and then do /ban