Install a Fuller's PokePack: cobblemon / pokemon modpack server through the Control Panel (Servers → Select your server → Game servers → Add Game Server → Fuller's PokePack: cobblemon / pokemon modpack)
There was a bit of frustration/confusion about which size server I needed for the modpack I was using so I had to keep upgrading the server until I got the right package. After that though the server has run great and I have no real complaints.