First, you need to add console. To do this, right click your Halo icon, go to properties, and add "-console" to the end of the target line. Once you have this done correctly, when you are the host of a game in Halo PC hit the "`" key (below escape) to bring up a place at the bottom of your screen where you can type commands.
To kick/ban: The first step is to type 'sv_players'
A list will show up, showing the names of players in your server, along with numbers. Say a player named "Jimmy" is being a straight up asshole. Type 'sv_players', and you will see Jimmy is number '1' or something like that.
So you decide to just kick Jimmy, then hopefully he will have learned his lesson. So type in "sv_kick 1" and it will say "Jimmy Quit" at the side where it says kills and conversations.
However, kicks don't always do justice. If Jimmy comes back and is still the same asshole he was before, type in "sv_ban 1" and he will be banned from all of your servers for good. However, be sure to look up his number, because his number will have changed because he rejoined the server.
Also, this will help.