Stardates Explained

You don't understand the stardates?
Take, for example, 20100924.1000.

Let me stick some spaces in some helpful places:
2010 09 24 . 10 00

That better?

20100924 means 24th Sep 2010, and
1000 is in 24-hour clock format, IE 10:00AM

Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how they work.

Events on this stardate