The simplest, least expensive way to begin is with a Bluetooth receiver plugged into one of the analog inputs on your amp. That will let you test the concept using Spotify, Pandora, Amazon Music, internet radio and other sources. The quality of Bluetooth transmission isn’t what you get from a CD but it may be good enough for awhile, particularly if you pick a receiver with aptX HD built in. One of my friends with a full McIntosh stack and Nola speakers is quite happy with a $149 Bluetooth receiver for casual listening.
Pick one with good customer reviews from this page in your price range and give it a try.
https://amzn.to/38p3kMcIf you pick one with digital output you could add a DAC between it and the amp to improve the sound but I wouldn't spend a lot of money on that solution rather than moving to a streamer that would use WiFi rather than Bluetooth.