How to use tables inside tables?

Sorry for asking such a simple question, but for some reason I can't figure out why this table isn't working?

items = {}
items[1]['Name'] = 'A killing machine'
items[1]['Desc'] = "Nobody can afford it.. it's unknown why it's so expensive.."
items[1]['Cost'] = 9999999999999999999999999999999999999999999999999999999999999999999

I also tried..

items = {}
items[1]['Name'] = {'A killing machine'}
items[1]['Desc'] = {"Nobody can afford it.. it's unknown why it's so expensive.."}
items[1]['Cost'] = {9999999999999999999999999999999999999999999999999999999999999999999}

I have plenty of experience, am I just forgetting something again?

Here's a clearer way to think about it:

-- on its own, an item is an object:
local item = {}
item.Name = "Blah"
item.Desc = "foo foo foo"
item.Cost = 999
-- (it exists without having to worry about its context,`items`)

-- you just happen to put that object into another one:
items[1] = item

Of course, you can also write this as table literals:

local item = {
	Name = "Blah",
	Desc = "foo foo foo",
	Cost = 999
}

items = {item}