If you own a Realtek RTL8812AU based product like Alfa AWUS036AC or AWUS036ACH and are having issues with Kali, we recommend you read our knowledge base articles that can help get you going.
Go to our help center and click on the category "Alfa AWUS036AC AWUS036ACH AWUS036EAC". Then click on the subcategory "Linux/Kali help".
There we have some great article including one showing how to install the item on Kali 2018.2
If you need additional help, we recommend posting in actual Linux or Kali forums as Linux is a community supported operating system. Our blog post comments are not regularly monitored. You can reach out to our support team with questions and feedback, but please note our support staff can only offer guidance on Linux related issues are not able to provide walkthroughs, step by step instructions, or guaranteed solutions for Linux use.