Page Likes
You can also use page likes to generate a lookalike audience. The steps are
similar but let’s quickly have a look. This time when you create your custom
audience, select Events. Facebook will bring up a new screen which will ask
you to select a Facebook page from the drop-down list (if you only have one
page, that’s what will be there). Make sure that you select People that have
engaged from the drop-down list above the Facebook page, and then set the
number of days that you want to use for the metric. From here on out, the
instructions are the same.