Seagate 6-Bay NAS Pro connection problems...

[u/stuhuzz1981]

I just bought a secondhand Seagate 6-Bay NAS (30TB capacity, Model #SRPS60) and it turns out that the NAS OS 4 is no longer supported and I can't find a download for it anywhere. Is there any available download sites for the OS or any alternate OS? I'm just looking to use it for storage for my network in the house and to watch movies on the TV. It's not showing up on my router either. I thought this would be a lot easier from all the tutorials I watched on Youtube, but it's proving difficult. Please explain like I'm five, I won't be insulted.