First, make sure internet is working and that you're connected to your local wifi network (for now we don't want to connect via your mobile provider). If you need that too, we'll tackle that next. First, we need it to work via local network, wifi.
You connect to webgizmo with a browser, right. In the address bar you use a hostname or ip address, like so:
http://hostname:52199/
or, with an ip address, like so:
http://192.168.0.10:52199/
These are just examples, hostname or the numerical notation 192.168.0.10 will be different in your case. They will be from your library server. Again, this will be in the address bar in your browser when you connect to webgizmo.
When you open Gizmo, tap the three dots in the upper right hand corner. Choose Mode.
Choose New Server ...
type in the address from webgizmo, without the 'http://' and no trailing '/'. It would look like this:
hostname:52199
or
192.168.0.10:52199
Tap 'Go'.
This should work if webgizmo works from the same device.