We put a new battery in and as soon as we hook the + the horn wont stop going off. Does anyone know how to fix it? Or any advice thank you.

 

Alarm maybe?

What was happening before removing the battery?

 

The car sat for a year we just put a new battery in but the car alarm wont turn off. Even while the cars off the alarm is still going off.

 

Need the answer that Grim asked, but if the battery originally ion the Mazda was replaced because it was completely dead and less then 7 volts you can then look at :
If you mean that the horn is going off constantly and not intermittingly like an alarm, then pull the horn fuse. Check the actuator button on the steering wheel that it at least feels like it is functioning properly, and it not cracked or broken.
If after this the horn still continually is active, then you will need to dissemble the horn actuator from the steering wheel and do a more careful inspection or just replace it.

 

Before replacing thr car ran fine just sat for a year because it needed some front end work. And that was it no motor problems. We got a battery and the alarm for thef mode is on. The car alarm wont stop going off. So we took the fuse out for the horn. But all other lights are still flashing

 

Any vehicle that remains connected to a battery source for a year can develop electrical issues. If alarm, you mean an aftermarket unit then your problem is not within the scope of trouble shooting and you must refer to the manufacture or supplier of the alarm system you installed.