Q: what happens if you accidentally interrupt the install /download process, without meaning to?

I thought I was in the process of downloading the free OS X Mavericks app-

and went to the dock to click on it, but accidentally removed it from the dock, which caused it to: poof disappear.

I don't know how to undo that, or retry downloading- but the app store continues to indicate it's 'downloading' and I can't seem to restart the process, without the update being downloaded anywhere.

Can anyone help?  And I haven't caused any serious 'damage' /malfunction to an already glitchy Macbook Pro, with this move?

Thanks*