Alarm will not turn off after installing a new battery?

This can happen when you have a voltage spike when the new battery was connected. I would remove the negative battery cable and leave it overnight and reconnect it the next morning. This guide may help as well:

https://www.2carpros.com/articles/how-to-reset-a-security-system

Also, I would try a hard reboot of the electrical system.

https://www.2carpros.com/articles/step-by-step-guide-performing-a-hard-system-reboot-for-your-vehicles-electronics-systems

Please go over these guides and get back to us.

Did you disconnect the battery overnight? If so, it sounds like the access/start authorization control module, or the electrical system control module has gone out. We should do a CAN scan to see if any codes are stores so we don't replace the incorrect part. You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon.

Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Please go over these guides and get back to us.

Okay, well since the hard reboot and disconnection overnight didn't help, we should do the CAN scan to see if any codes are stored. Let me know what you find.

You can get a CAN scanner (Controller Area Network) which will work on most cars from Amazon. We need to gather codes to see which direction to go in to fix the car.