There are several ways to install WordPress plugin, we do prefer using FTP but you can choose other ways. Please read more about plugin installation on the official website at http://codex.wordpress.org/Managing_Plugins
If you choose to use FTP, please do the following:
Step 1: Please unzip the main zip file that you downloaded from ThemeForest and open “Plugins” folder;
Step 2: There you can find Revolution slider folder;
Step 3: Please find revolution installable.zip file there;
Step 4: Unzip it and upload to Plugin folder to the wp-content/plugins folder in your WordPress directory online via FTP.;
Step 5: Log into your WordPress admin dashboard and activate “Revolution slider” plugin in the Plugins => Installed Plugins section;
Step 6: Once the plugin is activated, you can start creating the slides.
Step 7: Do not forget to read the slider documentation for obtatining information.