No Wi-fi adapter found after installing Ubuntu 20.04

I have recently installed Ubuntu 20.04 along with Windows 10. During installation of Ubuntu, under option "Updates and other software" I have selected "Install third party software for graphics and wi-fi hardware and additional media formats". After Installing Ubuntu, my Wi-fi is not working. When I open "Software and updates" in "Additional Drivers", if I select "Using Broadcom 802.11 Linux STA wireless driver….", then "Apply Changes" button is disabled.
What should I do to run wi-fi driver. Please help.