Sonew Two Way Intercom Doorphone,Wired Telephone Style Villa Home Office Non Visual Interphone White

Is it push to talk or you just pick up the phone on both ends and start talking? it is for my elderly parents, they do not understand ptt concept

Do the phones alarm each other loudly when you try to call one another?

Does the phone come supplied with a wall mounting bracket?

How to connect and make it able to communicate with each other?