Yes, I read all docs available on link Cloud - GL.iNet Docs, also reading what in the link Site-to-Site Network - GL.iNet you suggested, I see a good composition of advertising that appears the sign of more time spent to encourage to buy rather than to understand.
I spent a lot of time try to understand the hidden message that could be in those few words that should explain how to use the S2S once created:

### Testing the Site to Site connection

Now the Site to Site network is created and started, let’s test the connection.

Use your PC or Phone to connect to one of the Node of this Site to Site, and use browser to access another Node’s LAN ip, if you see the login page, the connection between these two nodes is worked.

For example, my PC connect to Node 1 device, and then I use browser to access Main Node’s LAN IP (192.168.48.1), if I see the login page, it means the connection between Node1 and Main Node is worked.

But whoever wrote, it was unable to explain anything