Congratulations on the new addition to your life, and thank you for rescuing.
Try feeding him his food by hand. I hand fed Max his first year, and had to play games with him.
3 days isn't a long time. Be patient while he adjusts. Hide your anxiety about him eating. When not hand feeding his food, put it in dish and leave him alone. Have designated meal times. Announce happily when it is breakfast, lunch, and dinner, then serve happily and leave him alone.
If he doesn't eat it after an hour or two, toss it. Don't expect him to eat stale food and mistake that for not eating. My boys hate stale food, not that they would leave any around that long.
We use 5 pound resealable bags and the boys are really happy when the fresh bag gets opened.
Don't get into the habit of feeding off your plate. You will encourage begging and he will never want his own food. Good luck!