To Upgrade from Sign-up Sheet Free to Pro, follow one of the methods below. Note that as of version 2.1+ you can run the free and pro versions side by side. You will retain all your current sheets and signups.
Log into your WordPress Admin and go to Plugins > Add New
Click “Upload” from the menu at the top
Choose the zip file you downloaded and click “Install Now”, then “Activate”
Download the zip file and extract it
Copy/paste the “sign-up-sheets-pro” folder from the zip file into your WordPress “plugins” directory
Activate the Sign-up Sheets Pro plugin from your admin “Plugins” screen