problem
After the system is installed, the display is provided >> WiFi: No WiFi adapter
Replace NIC driver
Open the software and additional driver updates >> see Broadcom bar chart like the one below, there are no second term in this:
any, would not be the next step, a check directly available drive, then "Apply Changes."
Wait a moment, you can see the upper right corner more options a wireless connection.
Without such a drive, then repeat the replacement source software, the card can be used until the emergence drive.
Replacement source software
Applications which open "software and updates" under the "Ubuntu Software" tab "downloaded from the" choose a suitable source, such as Ali cloud or something.
Then you may make some software updates about under the new source, the update thousand million.