You've probably already done this by now, but it's worth mentioning that keeping it open likely won't do you any good. Close out the game, relaunch the game, and do what you were doing before and see if it crashes again.

If you've crashed again while doing the same thing, make note of what you were doing and how you were doing it. This could help pinpoint exactly where the error occured, and lead to a much less painful debugging process for the developers.

In order to provide useful information to the developers to resolve the crash you've experienced, you'll need to provide an error log.
This can be done by going to the start menu and typing event viewer, like below.




















Once inside the event viewer, you'll need to expand the section labeled "Windows Logs" by left clicking on the white triangle beside it, then select "Application" by left clicking on the label.




















Next, you will want to look for recent errors (Red circles with white exclamation marks). Chances are, it will be labeled " .NET Runtime" under the "Source" Column. Left Click on this error to pull up the crash logs. (Click on the picture to make it larger)












To report the bug, hop on over to the discussion board and make a new discussion. You can make the title something along the lines of "BUG: Crash when _______". Explain what you were doing and how you were doing it, then paste in the crash logs that you obtained via above. An example of this can be found here. If you can, it doesn't hurt to add your system specifications, such as your operating system, GPU (graphics card), CPU (processor), how much RAM (memory) you have, as well as your screen's resolution.

Congratulations! If you've followed these steps, it should make the devs' lives much easier, and it should also get your bug fixed faster (though hopefully you won't run into any)! Thanks for submitting the bug/crash you've found, and indirectly making the game better because of it!