Class limter

How do i make it so u can have only so many of 1 class, is this is the server or something u add to the map?

it's the server. We used to have a highlander server that only allowed one per class.
I'm not sure how it was done...

All the admin mods should do it.
I would use BeetlesMod or SourceMod.
BM is easier to configure.  I can help you out if needed.

for highlanders there is a specific highlander plugin on the sourcemod site

for class limiting there are 2 class limiting plugins on sourcemod, though it should be noted that they dont work 100% and you will sometimes get more than your set limit of one class.
Ive even seen the plugin fail so badly that it allowed 1 engineer to build two sentries...go figure.

Yea, one of the plugins usually pretty reliable, but sometimes screws up so badly that when you change class, you get your new class's health and abilities, but keep the weapons from your old class.

Examples:

Heavy with Sniper Rifle

Scout with minigun

In general though, I've found the plugin is more than 99% effective.

Here's the plugin I use, it's pretty straightforward, though it lacks dynamic class limits (ie different limits for different numbers of people). The bugginess can be incredibly game-breaking, though so far I've been lucky in that the bug (while incredibly rare) has only struck a few people who were responsible enough not to abuse it.

I've had little to no issues in recent times with BM's class limiter.  At least nothing bad that I know of.