Timeline Editing

[rofl]

Hey, I'm trying to make an app that has a timeline, with multiple tracks.

The idea is this: a sound file in the project can be put on the timeline as many times as desired, where desired.

So, for example, if I had a recording of someone saying "yo" and also "hey" or something, they could put those as many times as they want, like:

[yo][yo] [yo] [yo] [yo]
[hey] [hey] [hey][hey]

So they CAN overlap, but don't have to.

For the record, I know there's already a few apps out there that do this; I just want to learn about it, because it sounds like a very interesting project. Not to mention, if I make my own, I don't need to buy one. :P

So any idea on how I can get this started? I have the sound files in the project already, so it's simply calling to the files, and hopefully saving the projects in a plist or something, and the last step would be exporting to an mp3 or such.

Can I get some help on starting with the timeline idea? About adding and moving tracks left and right, say like this:

Double tap to create a new instance of the loop.
Double tap on a current instance, and hold second tap, dragging it left and right.
Single tap/drag to scroll left or right.
Single tap on an instance to pop up an alert message saying "Delete Instance?" and having yes/no buttons.

Thanks for any and all help!