Will not start after replacing the drained battery?

This is my mother’s car, and it is mint and never goes anywhere. The battery draine and I replaced it and now it won’t start. It cranks but it’s like no fuel going to it maybe because it’s in anti-theft mode? There is an icon on the console reflecting a steering wheel with an explanation mark. I have the key fobs and can turn alarm on and off, but it still won’t start.