If you're an Android or Google account user, this is really simple but must be done from the web browser at https://calendar.google.com
On the left side of the screen you should see "Add a Friend's Calendar" or "Add a Coworker's Calendar". In the text box, enter the email address firstname.lastname@example.org and hit enter. There should be a new entry for the calendar under Other Calendars. Feel free to change it to a different color so it stands out from the rest of your calendar entries.
If you're using the built in Calendar app on iPhone or other calendar applications, click this link & confirm you want to subscribe to the calendar.
iPhone users NEED to open the link with Safari for it to work correctly!
If your application does not like the previous link, you can use the following URL to set up a manual subscription. Consult your software's help files for more information on creating a manual subscription. This iCal feed contains the same data. - https://calendar.google.com/calendar/ical/calendar%40troop671bsa.org/public/basic.ics
Send an email to Mr. Short if you run into problems.