Benefits of using child theme are described in details here. In this article, you will learn how to upload and install a child theme.
Step 1 – Download child theme
A child theme can be found in All files & documentation file after you download it from ThemeForest.
After downloading, extract the archive and go to Child Theme folder, there you will see the file named noor-child.zip
Step 2 – Upload child theme
The process is the same as installing parent theme except in this case you need to upload the noor-child.zip file.
Go to Appearance > Themes and click Add New then choose Upload Theme and upload noor-child.zip installable WordPress file then click Install Now.
After the theme is uploaded and installed click Activate and you will see the Welcome screen of Noor.