When creating a new web link, you can choose from a list of predefined web links rather than entering your own. This is particularly useful for common sites that have site dependencies necessary to make them function when used with Site Lock. See the section of this guide on Dependencies for more information.
To add a predefined web link, go to the Web links menu, then click Add Web Links. In this sidebar, select the Predefined radio button at the top of the form.
Select one of the predefined links, then click Add. In many cases, you'll want to then select and edit the link to configure it to your needs. For example, the "YouTube Video" link type will require you to edit the URL to include the ID of the specific YouTube video you wish to link to.