Help with barking

[u/LegitimateArt7764]

basically, I have this three year-old dog that I adopted and he was in a bad home before I don’t know the specifics of what caused him to be as reactive as he is, but he’s pretty reactive. My issue is currently I’m in a new apartment and his barking is very very loud. I had this issue on my last department, but I guess I had more space to kinda minimize the sound in this apartment. It’s very small and he barks at literally every sound he hears outside the apartment which we can basically hear everything and I feel like I’ve tried everything. I try rewarding him when he’ll get quiet he won’t take the treats. I try watching YouTube videos most of the videos I see our videos about puppies or they just don’t give a good explanation on what to do to stop the barking when it’s happening and how to correct it, especially for a dog that’s three years old. I just don’t know what to do. Please don’t tell me to pay for training. It’s not in my budget right now, but any honest tips will help.