What the existing connection tells
Many questions after installation are not about hardware but about who manages the app, how a second user is added or how you see which door is opened.
A mounted intercom is only ready when users can independently make calls, answer, manage access and ask for help with the right information.

Many questions after installation are not about hardware but about who manages the app, how a second user is added or how you see which door is opened.
Create a delivery list with outgoing mail, incoming mail, app, doorbell and management account. Check which functions have been actually agreed upon and which user receives the explanation.
Take the control over-site and provide a short, system-related instruction. Record contact details and basic information without putting passwords in an open document.
Let the user answer a call themselves, open a door, and add or invite a second account. Note outstanding items and only close when the agreed route works.
At least a function test, user explanation and clear management information.
The owner must have recovery and management control, without the sensitive data being shared in an insecure manner.