Install a NeoForge 20.4.245 (MC 1.20.4 ) server through the Control Panel (Servers → Select your server → Game servers → Add Game Server → NeoForge 20.4.245 (MC 1.20.4 ))
Fantastic service for a great price. Very easy to download packs onto the server. My only issues and complaints are it doesn't have every pack available and the FTP process is tedious. I also can't see what version the packs they have downloaded on the site are and if they correspond with version info.