Follow the following steps to get the themes in the "theme" section of the "Customize" tab:
- Download a theme from any website and extract the theme in a folder.
- Copy the folder in the "themes" folder of the "BlogEngine(web)" folder.
- Now go to the administration section and log off.
- Log In again to get the themes available in the "Installed" category.
It is possible that you might get several errors like ".master.cs" not found.
To fix such bugs, go to the "theme_name" folder --> content --> themes --> theme_name, and copy all the files and folders and paste them in the "theme_name" folder.
The errors would be generally due to improper paths of files and images.
It is also possible that you might get pages that donot have images or pages without CSS properties.
Implementing the above steps would fix all of them.
-Tushar Sharma