If you forgot your password, there is a recovery process. There is an account used as your recovery agent for most people this is either @steem or @anonsteem.
You can change this, but it isn't documented anywhere and been asked a few times about how to do it.
So I can basically put a witness I know as the one who will be my recovery agent?
If you are not sure, then you likely don't need to worry about it. Just use the default @steem recovery process.