Welcome aboard.

To begin with, you should eat what you store, and store what you eat. This means that planning for long term storage should focus on items you will be used to eating regularly. Unless your purpose for long term food storage is solely for barter after things go bad, you should stock foods that you are familiar with. This could mean adjusting your diet now to include items that store well, and reducing those items that are perishable or not otherwise suitable for storage.

Most inherently long term storage items, such as legumes and some grains, do not let themselves to regular consumption on their own. Either they need to be combined with other items, or processed into more suitable media, like flour or meal.

A strong recommendation is to develop skills and acquire processing equipment so that you can use to put up a variety of foods for long term.

Of course, long term is a relative thing. Are you looking for 1 or 2 year storage, 5 year, 10 year, 25 year? There are food items that fit all these timelines. For the longest term, freeze dried foods stored in #10 cans seem to have the longest shelf life. Wheat can be held almost indefinitely if it is kept dry and whole (unground). In the bible Joseph advised Pharoah to put up wheat for the coming 10 year famine. There are reports of wheat grain being found in clay pots in archeological sites dating back hundreds to thousands of years, and still germinated. Likewise with some legumes. Freeze dried foods in mylar pouches and MREs will last 5-10 years if handled sensibly. Dehydrated foods can be stored up to 5 years, though they will be better consumed within 2 years or less. Canned goods will generally hold up for a couple years. I am still eating on meat that I canned almost three years now, though the consistency is not the best. It is still safe and provides nourishment.

Canning and dehydrating food items are processes we can manage economically and with some basic proficiency. But for the long term planner, Cans of freeze dried foods like vegetables and fruits, along with powdered milk, powdered eggs, sugar, spices, and various freeze dried meats will supplement large plastic pails full of wheat, beans, pasta, and mashed potato mixes.

Mylar is aluminized plastic film. It is better than plastic vacuum bag systems or ziplocs, but not as good as retort bags, which are laminates of aluminum and plastic; more robust and durable. Cans are better than bags, and jars are better than cans. Plastic pails with gamma lids will contain 5 gallons of food, and can be combined with mylar bags and oxygen/moisture absorbers to prolong the storage life of the contents.

This is just a brief of all the information available to you to make better decisions. Doing the research yourself will be more valuable in the long run.