Please, put the code from the following examples into the textarea “Custom PHP code” in the section “Misc Settings” (except codes from section “Add Fields”!).
Note: Codes from section “Add Fields” should be added via Code Snippets plugin (otherwise put it to the functions.php of your current theme). Users of the PRO version should set mode “Run snippet everywhere” in the snippet if they use the scheduled jobs!
See this documentation article to know more about naming for hooks/filters.