Download & install CurseForge https://curseforge.overwolf.com/
Search for Lapito's Galacticraft:
Select Versions and install Lapito's Galacticraft-126.96.36.199:
Click Minecraft on left and click on Lapito's Galacticraft image, NOT the Play button, to get to this screen:
Click Submenu and select Profile Options:
Uncheck Use System Memory Settings and set RAM to at least 5GB, 7+GB recommended if you can spare it.
Launch game through CurseForge and login using either your MS or Mojang account (depends if you have migrated your account yet
Add server: 502krew.com:2144
Build whatever you want but don't mess with other people's stuff and don't touch stuff in the Space Center unless you know what it will do!
You will start with books in your inventory teaching about some of the mods included - Highly recommend checking out Materials And You which teaches about Tinker Tools - everything you need except mats for Tinker Tools is already in the main spawn area.
In Curseforge right click on your instance icon and select Open Folder
Download Pixelmon Addon mods and resource pack from this link.
Unizip files into appropriate sub-folder (do not unzip the ThePixelmonOST.zip archive, just place the file into the resourcepacks folder)
Default "Send out Pokemon" button is R. You need to go into your keybindings and unbind other mods using that button - OR change it to a different unused button.