First you think about if the channel is about something you invented your self(#), or if it is a channel about a subject that someone else invented(##). These are the FreeNode guidelines.
/msg chanserv REGISTER ##channelname password
Now you gonna get acces. If you only have one # you can set the access to 50, but if you have ## your access is 49.
/msg chanserv ACCESS ##channelname ADD yournick 50
Make sure that chanserv has noticed what you have been written, and accepted it. Or else you cant go on.
/msg Chanserv SET ##channelname GUARD on
If you want your friend to have some ops in the channel, 44 is what he needs to help you with eventually securityproblems. You can deside your self, if you want to give him less.
/msg Chanserv ACCESS ##channelname ADD friendsnick 44
Im not sure why you have to put both the secure and the guard. But better save than sorry.
/msg Chanserv SET ##channelname SECURE on
If you dont want to have your channel anymore:
/msg Chanserv DROP ##channelname password
Here I'm pasting my own blacklist of people I dont want in my channels. I'm not sure what they are doing (maybe scanning ports), but they dont say anything, and im not too comfortable with that.
Luckily on FreeNode I haven't had that much trouble as I did on IrCQnet.