0. have some basic ingredients on hand

(Part of The Cookbook)

Some things last for a recipe, like meats and produce. And some things last for several recipes, like these:

salt (kosher is best)
pepper (nice, freshly ground pepper makes a big difference in flavor)
high-heat cooking oil, like canola oil, vegetable oil, grapeseed oil or peanut oil
vinegar or extra lemons
unsalted butter
olive oil

I would say that if you're just getting started cooking from scratch, you need at least these things. You may think that it's a short list and if you think that, you're right. You use mostly fresh ingredients when you cook from scratch.

-1. have some basic equipment

(Part of The Cookbook)

You need tools for any job. You need cooking tools for cooking jobs, and I think you should have at least these tools:

a chef's knife
a bread knife
a smaller knife that you like

a cutting board

a medium saucepan (2-3 qts)
a medium saute pan (around 8-10 inches)
a large pot (around 2 gallons)
a large wire mesh strainer
a couple spoons, one slotted
a rubber spatula
a baking dish (preferably with a cover)
a sheet pan or two
2-3 mixing bowls, at least one large
a whisk
a pair of metal tongs

I won't insult you by telling you to get things as basic as dinnerware, flatware & can openers, because you wouldn't try to open a can with a knife anyway. Messy. Blood and crying.