How to play LAN with friends?

Hey guys,
I want to play with my friends on a LAN server, but we don't know how. We tried with hamachi but things didn't work out. Are we doing something wrong? Please if anyone here had similar issue, you can tell us how to fix it.
Thanks in advance!

Connections. Maybe they are blocked by some firewall and/or closed ports. If you are the host you should add a rule to your firewall to allow connections from CS and Hamachi (or just disable the firewall if you are a badass). To avoid hamachi you need to open the 27015 port from your router settings so everyone can join to your game directly from "View Info" in Steam.