To save a single record as favorite, navigate to the record, then simply click the corresponding Add Record to Favorites menu item.
The following window will pop-up, prompting you to enter a name for the favorite and to select a folder (on creating folders, see the online help section titled "Managing your favorites").
If you don't want the window to popup but rather immediately add the favorites to the menu, then click the Options... menu item and under the General tab, check the Do not show the "Add Record to Favorites" window.