To use Web Export install it in Adobe XD and then open a project.
Install the plugin in Adobe XD
Open your project and select an artboard
Go to Web Export > Export Artboard and click Export
These steps create the web pages. You can view HTML pages on your computer with your browser.
To put your web pages online there are a few more steps.
Transfer your pages to a computer connected to the web
Read the following guide to put your pages online.