Shortening the URL for html5 - index.html overight URLs

Hi Forum guys

I went into the index file saved here:

C:/inetpub/wwwroot/Html5Viewer/index.html

to change the URL of one of my sites. However, when navigating to the correct section

the only URL available here for me to change is of the most recent site I built. I cannot seem to find any of the other URLS for the other 5 sites I have.

According to the GCX essentials training I undertook last week, this is the only location where you can change your URL string.

Where are all the other site's URL stored? Can anyone help??