this is quite simple. Get a program which unlocks the console. In the console type the command, Status. Some names should pop up, find the name who u want to kick, and the left side of his name there shuld be a number 1-18. once you have that number type 'sv_kickbantime 1' and press enter. Now type 'tempbanclient x' remember the number u got from typing status? put that where the x is. you can increase the ban time to 3600 (3600 is max)seconds.
Good luck :]