GETTING STARTED WITH LONG-TERM FOOD STORAGE
Once you have enough food & water for the household for 3 days, you need more.
Depending on where you live, help may not be coming for weeks. And in the case of a societally-disruptive event, you may be on your own for a really LONG time. I'm not Mormon, but I appreciate the L.D.S. emphasis on preparedness, especially their recommendation to all of their church members to have a 12-month supply of food on hand at all times.
If you're just starting out, though, try not to get overwhelmed.
Break the task into bite-sized chunks!