GNU/Linux Ubuntu 18.04 Realtek rtl8821ae Driver Installation Guide
Hi! The linked Tutorial shows you Step-by-Step How to Install Realtek rtl8821ae Wireless Driver for Ubuntu 18.04 Bionic LTS GNU/Linux.
And the Realtek rtl8821ae Ubuntu 18.04 Driver Installation is Quick & Easy, involving at most the execution of some Basic Shell Commands.
Finally, if you have Different Card then See this Other Guide: How to Install Realtek Wifi Drivers on Ubuntu.

Installing Realtek rtl8821ae Driver Ubuntu
How to Install Realtek rtl8821ae Wifi Driver for Ubuntu 18.04
Realtek rtl8821ae Ubuntu Driver SetupHere Ubuntu Realtek rtl8821ae Installation