In order to install the theme you need to have a WordPress copy already installed on your own server.
Below are some useful links for WordPress information:
NOTE: Once you have downloaded the theme package from ThemeForest you must unzip it and upload only the inner zip file named ViewTube.zip.
Step by step instructions:
1. log in to your WordPress site’s administration area
2 . Navigate to Appearance > Themes > Add New > Upload theme
3 . Click on the “Add New” button, then click on the “Upload Theme” button and also check below image
4 . Upload the theme zip file named ViewTube.zip
5 . Click “Activate”
If this method fails we recommend uploading the theme via FTP. Open your FTP client, move to your WordPress installation path /wp-content/themes and upload the unzipped ViewTube folder.
After the upload is complete navigate to Appearance > Themes and activate the theme.