Download
Download the zip file on the downloads page of your Time Slot account.
Install
On your website, go to the Plugins page and deactivate the Time Slot standard version of the plugin. You will not lose any of your settings. Now click the Add New button at the top of the plugins page. Click the Upload Plugin button, then the Browse button to find the zip file you downloaded. Click the Install Now button.
Activate
Once the plugin has finished installing, return to the plugins page. Activate the Time Slot Pro plugin, and delete the Time Slot standard plugin.
License
Copy the license key from the your account on the Time Slot website. Go to the Time Slot general settings page on your website, and enter you license key and click the Save Changes button. Click the Activate License button, and you are ready to use the Pro settings!