1 - Use CurseForge app found here - https://download.curseforge.com/ - its free!
2 - Install program
3 - Once application is open select Minecraft
4 - The page you'll get taken to has a search bar at the top, search for The Pixelmon Modpack. (Logo of the pack is below )
5 - Press install and wait for it to completely install.
6 - Launch game and add our server. IP is in our discord
7 - Happy Pokemon Hunting!