When you enter a value in the H1 Heading field, that value will be used as the front-end page title, appearing in an H1 tag. If you don't specify alternate names, the H1 Heading will also be used in front-end navigation contexts (e.g., drop down menus, the subnav, and the crumb trail), as well as throughout the AR5 back end. In many cases, the H1 Heading field alone will be sufficient to satisfy your page naming requirements.
Alternate Nav Name
If you wish to use a label for your page in front-end navigation that's different from the H1 Heading, you can enter it in the Alternate Nav Name field.
Alternate Admin Name
By default, AR5 will use the Alternate Nav Name to label your page on the back end, and if there isn't one it will use the H1 Heading. If instead you want to specify a name for use within the AR5 back end only, enter it in the Alternate Admin Name field.
When you first create a page, a blank Friendly URL field will be available. If you don't enter one yourself, AR5 will automatically generate one based on the Alternate Nav Name (or, if that's blank, on the H1 Heading) and will fill it in when the new page is saved. Most of the time, the automatically generated friendly URL is all you need and is what makes sense for the page. If you wish to, however, you can manually enter a friendly URL while creating the page or when editing it later.