Login to your WordPress site from wp-admin and navigate to the Plugins module. Here you can see the Add New Button. Click on ‘Add New’ button which will redirect you to Add Plugins Page.
Click on ‘Upload Plugin’ button. Browse the ‘sf-customer-portal’ zip and Install the Plugin.
Go to Installed Plugins screen. Here, you can see the Salesforce Customer Portal plugin was successfully installed. But still, it’s Inactive.
Click on ‘Activate’ to activate this newly installed plugin.