next morning the car would not start?

I drove to a neighborhood shop to buy some stuff. Where I parked was not permitted so I put the hazard lights on. When I came back, the car couldn’t start so I thought the battery had run down. When the breakdown service came and supported my battery with theirs, the car started. I was told to let it steam for about 45 minutes to recharge the battery which I did. I later drove around with the car and finally parked it. The next morning the car couldn’t start though the dashboard lights were bright enough. I thought the battery had exhausted its lifespan, so I ordered a new battery. When the new battery came, I installed it but still the car did not start. The engine was not turning even with the dashboard lights showing very bright. Now I don’t know what else to do. Thanks.