1. Download Minecraft from
http://minecraft.net and place it in a location you are comfortable with like for example: C:\Games\Minecraft
2. Run Minecraft. The launcher should come up with a screen similar to this:
Log in with your Minecraft.net user account.
3. Create a new profile. After you have successfully logged in to Minecraft you should see something like this:
Click the New Profile button on the bottom left.
4. Create a profile.
Give it a name you can remember like: Snapshot.
Select: Enable experimental development versions ("snapshots").
And use version: "Use Latest Version".
Then click the Save Profile button.
5. Back on the launcher select the profile you just made. In the case of this tutorial it will be called: "Snapshot" and click the big Play button.
Sometimes the launcher "forgets" you already logged in, or gives you some weird message about already being logged in or not. It's stupid, and you often have to log in again and again and again... It's just something we have to learn to live with until Mojang fixes these annoyances.
6. After Minecraft has started, select Multiplayer.
Then click the Add server button.
Give it a good name like: HappyDiggers Snapshot Server
And fill in the following Server Address:
snapshot.happydiggers.net:25566
After you click Done, you will be taken to your server list. Click on the server you just added and then click Join Server.