To install Backdrop CMS, follow these steps:
Download Backdrop CMS: Go to the official Backdrop CMS website (https://backdropcms.org/download) and download the latest stable release of the software.
Unzip the Files: After the download is complete, unzip the downloaded file to a location of your choice on your web server.
Create a Database: Create a new database for Backdrop CMS to use. You can do this through your web hosting control panel or by using a tool like phpMyAdmin.