backing up to a NAS with Time Machine?

New to Mac, I am busy going from PC to Mac, I've successfully got my files over to the iMac, and am now trying to get my head around backing up.

I backed my PC up to 2 internal drives, an external drive attached to the PC and a NAS. I also used OneDrive for files that could be safely stored in the cloud.

I have a 2 Tb Seagate USB hard rive attached which TM identified as soon as I plugged it in and it is now regularly backing up to that.

I also have a NAS and with the PC I used that as part of a regular back up regime, along with a couple other drives. I want the Mac to back p to the NAS too but when I open TM prefs the NAS is not there at all, despite being visible in Finder.

SO, simply what do I have to do to get TM to see the NAS and start using that as well as the USB drive for backups?

Cheers, Steve

Hi thanks for that. The 2Tb USB drive was picked up by the Mac immediately and it formatted it then TM is doing it's stuff.

In that case I'll manually create a folder on the NAS and manually save my mac documents folder to it.

I use the NAS for backing up a Windows laptop too so can't format it just for the iMac.

I'll look for a suitable backup app for the Mac. I did something similar on the PC so no great hardship, I'm still getting my head around how the Mac stores it's files at the moment!