Watch youtube videos.
You say that you are an idiot and a freakin sucker
The most efficient way t host a minecraft server is ... Sorry but get Windows.
On the Minecraft download page, you can download a Vanilla (standard) Minecraft server for Windows, Mac, and (I think) Linux.
Use the hamachi server.
Watch youtube videos.
advertise on the forums
Create a server.
You can't
You need to have java 6 or later installed on your mac for a minecraft server jar to open correctly. If this doesn't work you can use a terminal command to run the jar.
You have to create a server and load the map to the server.
To run a Minecraft Server you will need to download the server software (See links below) and then enter the command... java -cp minecraft-server.jar com.mojang.minecraft.server.MinecraftServer ...into the Terminal. The Read Me file that comes with the Server download explains how to configure the server to your particular needs.