For most items, simply install them directly through the WordPress dashboard under Appearance > Themes > Add New > Upload Theme or Plugins > Add New > Upload Plugin. For ThemeForest themes, you must download, extract, and identify the theme installation directory by following the process described below:
1 Download the selected theme (ZIP file).
2 Extract it to a directory of your choice.
3 Open the extracted directory and look for the folder containing the image named screenshot.png or .jpg and the file style.css.
4 After locating the installation folder, upload it via FTP to the ‘wp-content/themes/themefolder‘ directory in your WordPress installation.
5 If you prefer to install it through the WordPress dashboard, simply compress this folder as a ZIP file (it cannot be RAR) and upload it under Appearance > Themes > Add New > Upload Theme.
6 Finally, go to Appearance > Themes and activate the installed theme.
The plugin installation process is similar, but there will be no screenshot image; instead, there will be PHP files.