Welcome to Qubes.
One of the important lessons to learn is that many problems arent
Qubes problems - they are issues in the distribution used in the qube -
in it’s template.
The Qubes docs don’t repeat things that can be found elsewhere.
You don’t say which version of Qubes you have installed.
At the top of the screen you’ll see a task bar, and in the right hand
corner you should see an icon of 2 computers, one behind the other -
this is the icon from sys-net that you use to control networking.
If all is well, you should be able to click on this icon, and see
the name of your WiFi router: select it and you should be prompted for
your WiFi password.
If you don’t see any WiFi networks or WiFi is not available, then it may
be that the WiFi adapter is not attached to sys-net.
Open the Qube Manager.
Shutdown sys-net.
Open settings, go the the Devices tab, and make sure that you have the
Network Controller for WiFi in the selected list. If it isn’t there, add
it, and restart sys-net.
If the controller is already attached to sys-net, it may be that it isn’t
working with the Fedora template that is the default. You can try using
a Debian template, by shutting down sys-net, and changing the Template
on the Basic tab of Settings.
(If you see warnings or are unable to shutdown sys-net when you try, you
can Right click on the sys-net icon in Manager and select Kill from the
menu.)