Redirect links, formerly "Old style tracking" work like any other link. To create a click the link always points to a script in your Post Affiliate Pro 4 (PAP4) installation folder including some affiliate variables of Post Affiliate Pro:

This click.php script creates a browser cookie in visitor's browser, registers a click to an affiliate with the particular refid and registers a per click commission (if defined) computed based on the campaign to which the banner identified by a_bid variable belongs. When the click is saved and browser cookie created, the Destination URL from this banner is used for redirection. So when you click on a link like
you will end up at the Destination URL (target URL) defined in the banner with ID represented by the value of a_bid in the link you have clicked.

If you want to rely on the Flash cookies, remember that this tracking method doesn't create Flash cookies.
This linking method is not recommended to use with social media like Facebook because they can be automatically blocked or marked as fraud.
NOTE: If you switch to this linking method globally, so at Configuration > Tracking settings > Affiliate linking method you switch to "Standard links (redirect)", then the General Affiliate Link will disappear. 
In case you still wish to have a general affiliate link while you are using Standard Links (redirect) linking method, then you can add a general affiliate link , but when you are adding it, then the base URL of the link must be like URL_TO_PostAffiliatePro/scripts/click.php . The link should be followed by ?a_aid={$refid}&a_bid=bannerID, where you need to replace "bannerID" with ID of the banner in which you have defined the desired URL to which this link should redirect.