I use Moode Audio and Volumio on two different RPis. There are plenty of other software options to choose from.
Below are a couple of links that are helpful:
Set up instructions can be found at
https://moodeaudio.org/
The instructions don't give info on image writing utilities, but I uses balenaEtcher
https://www.balena.io/etcher/
Basically you'll need:
1. An RPi. I would recommend and RPi4 2GB.
2. A case. I use this
this case. You can buy a cheaper case. You don't need a fan if you're running an RPi as a network streamer.
3. A power supply. The stanard RPi power supply for your location is sufficient.
You can connect your RPi to your DAC via USB.
How you use the RPi depends on what you're streaming. Are you streaming local files or using a streaming service (e.g. Spotify, Qobuz, Tidal), or both?