Step 1: Join our Discord:
https://discord.gg/2dVnmGk

Step 2: Get the most recent version of java x64: *
https://java.com/en/download/

Step 3: Get MultiMC (MMC):
https://multimc.org/

Step 4: Download CotM MMC instance:
https://centerofthemultiverse.net/launcher/cotm.zip

Step 5: Import and configure the instance:
https://github.com/MultiMC/MultiMC5/wiki/Import-Instance

Step 6: Run game, select/update optional mods, play!

Final Notes: The instance is pre-configured to run out of the box. We are also using voodoo magic to self-update when we push changes to the modpack! Part of this, however, is any fresh install WILL crash on first run. Do not be alarmed by this and just re-launch.

*: due to the amount of RAM needed to run CotM, 32-bit operating systems and java are NOT supported.