The Project Box in Notifications presents (on my computer) the same options as if I used "WIN" +"P" to configure dual monitors.
Choices being PC screen only, Duplicate, Extend, and Second screen only. Try "WIN" + "P" and select Duplicate.
As for the IP address if you did not set up the 192.168.1.XXX address then the address is likely DHCP which means that the Projector is requesting that an IP address be assigned and the Router is giving the Projector that IP address. And the IP address can change change each time the Projector connects to your home network.
Some network devices (printers, storage, scanners) use an assigned IP address that does not change - hence Static. However, the device needs to be configured accordingly but the process must also be coordinated with the host network router. Otherwise the router may assign the same address to another device and that does not end well. Sort of like two houses having same house number on the same street.
You do not need to hide the 192.168.1.XXX IP address. That is within one of the three private IP address ranges used for home and small business networks.
The terminology is confusing. For more information:
https://www.lifewire.com/what-is-a-private-ip-address-2625970
Just to help you become a bit more familiar with and comfortable with the concepts involved. Especially if the Projector does need to be statically configured to become part of the network. And consistently so.
What you do not want to reveal is the Public IP address that your ISP assigns to your router.
For the record - This Projector:
https://www.newegg.com/p/0FC-05GV-00060
So at that, I will move the thread to Home Audio. But I will keep a watch on the thread and see what develops.