WordPress ships with few default themes. However, you can easily customize the look and feel with the help of themes available either from official WordPress Gallery or any other third-party source. Normally, you will have to install one single WordPress theme file. If you purchase a premium theme, you will be required to install a child theme on top of the primary theme. The child theme will provide features not available in the primary theme.
Imagine, the case of Heatmap theme, where you have access to multiple child themes. However, the child theme will work only if you have installed the main theme. A child theme borrows all the features including the appearance of the parent theme. It is possible to modify the look and feel without touching the code of parent theme.
Normally, Child themes are used with WordPress theme frameworks such as Thesis, Genesis, and others. If you work with framework-based themes, you will be able to access powerful parent themes with a solid code base. If you are a developer, you can directly modify the code.
To install the WordPress Child Theme, you need to navigate to WordPress admin dashboard. Select Appearance | Themes option.
Select Add New button from the corresponding screen.
If the child theme is available on the official WordPress theme repository, you can just locate the theme using the search box. You can directly install the theme without downloading any files. This method will be useful for beginners or if you don’t have the knowledge to install a WordPress theme manually.
If you have access to a child theme in the form of a ZIP file, you need to select Upload Theme button. You need to locate the theme file using the Browse button and install the theme.
If you prefer, you can install the WordPress child theme using FTP. You have to download the FTP client software and log in using the credentials. After that, you should navigate to the relevant folder of your domain and open the wp-content/themes folder. You have to upload the file inside this folder.
You can install any WordPress Child theme using any one of the methods described above. However, you need to install the primary theme before proceeding to install any child theme. You should make sure to obtain the child theme from a reliable source.