Setting up guest network on t-mobile highspeed home internet

A true Guest network is on a DMZ meaning there is no connection between your network and the guest network. This would be for security purposes here is how we use a true guest network. Example my wife has a party a bunch of random people are coming over. They always want to hook up to wifi so we have a true guest network that they can use. They have access to the internet but no access to any of our devices on our private network. Kinda think of it as two totally separate routers like you and your neighbor. This is a true guest network again not that any of them are hackers but just good measure why should I even be sharing my main wifi password with them.

Businesses use this for customers so that customers are separated from for example the cash registers.

So what you are doing is giving yourself a sort of guest network it does have a seperate password if you want but there is communication between the networks unlike a true guest network.

Just so you totally understand say you have your main SSID called Main and now you setup another one called Guest and even give it a different password. Now you connect a laptop to Main and another laptop to Guest. From a network POV both of those laptops can see each other and communicate to each other. If this was a true guest network there would be completely no communication at all in any way.

But for your purpose it should work just fine.