Installing the Plugin
Installing Highlight and Share in the WordPress Admin Install from the WordPress Admin
Log into your WordPress admin (i.e., your dashboard)
Type in "Highlight and Share"
After activation, you can find the plugin's settings in the Dashboard under Settings->Highlight and Share.
Install via FTP
Download the plugin zip file
Unzip the plugin zip in a place you can remember for the next steps
Log into your FTP program of choice for your website
After activation, you will be taken to the plugin's settings screen.