local function what.the.hell

Okay. Calming down. And what I'm finding is that the Ansca Mobile Corona website is pretty awesome. I still have to figure out how to code, but they have sample apps that you can use to get started and see how the language works. They have a robust forum with people who seem to be quite patient and willing to help the noob (though the noobs could learn a thing or two about patience and manners).

So I'm still at a complete freakin' loss for how to do this, but I now feel a little confident that I have some help. I've been playing with a couple of the sample apps, copied in some other code I found on the site and kinda figuring stuff out. One problem (another problem) is that even the helpful forum people don't quite understand that some of us have no fracking idea how to move forward. I read a couple of tutorials that Corona users posted that were supposedly for the neophyte, but they failed to realize that they need to explain EVERYTHING. They'd put in a block of code and say: this does such-n-such. Which is nice, but I need to know how the code works and what each item does. For example:

     local background = display.newImage( "ground.png" )

So this one really is pretty self explanatory, except that what does the "local" mean? I'm not sure other than they say on the forum to use it to help with performance. Local seems to imply that it's doing its business locally. Fine. But if the "local" isn't there, how is that different? If it's not doing whatever locally anymore, just where is it doing it?

But, fine, I get it. This displays a file called "ground.png" and you've defined this image with the name "background". I assume that after display.xxx that you can put other stuff there that displays ... other stuff. And why "newImage"? Why not just display.image? Here are some more:

local function newCrate( ) --is "newCrate" a command? Or could you call it newBouncingBall if you wanted? Or do you need the "new"? Could you call it "local function crate"? Heck if I know.

local function button:tap( event ) --why the colon? Are button and tap just names or are they actual commands? Could this have been called "local function look:here( event )"?

So so confused.