Click Launch Options.
Make Sure Enable Snapshots is on and green.
Click Add New.
Click the dropdown for the Version box.
Select the Latest Snapshot. The numbers will change in each update and not match the pictures.
Confirm your new configuration at the bottom of the list.
Click the Minecraft logo to get back to the main screen.
Click the configuration drop-down on the play button.
Select your new snapshot configuration.
Success da big, green button will now launch the latest snapshot.
You can now join snap.fishsurvives.com ! yay!
If you don’t know how to add a new Multiplayer Server, here are instructions.