Add the School Calendar to Your Google Calendar

Go to the School Calendar.
Click the button at the bottom-right labelled, + Google Calendar.
When asked if you want to add the La Salle High School calendar to your calendar, click Yes, add this calendar.
You should now see events from the school calendar in your calendar.

Adding the Lunch Menu to your Google Calendar

Visit the Lunch Menu calendar
Click the button at the bottom-right labelled, + Google Calendar.
When asked if you want to add the La Salle High School calendar to your calendar, click Yes, add this calendar.
You should now see events from the lunch calendar in your calendar.