How do you host a multi-player survival game in Minecraft?
You need to download the multiplayer survival server. It can be found at https://minecraft.net/download at the bottom of the page.
You can now host a local multiplayer server without any additional software.
Start or continue your map in Single Player, press esc and select
"Open to Lan".
Other players can then join your game from the Multiplayer menu. The LAN game should be automatically detected.