how can i take out the civic dashboard so that i can connect a subwoofer?

Hi Panchio! That's a significant job and the most important thing about it is procedure, the order in which you do things. If your stereo is after market the auto audio shop will be a great source of help, otherwise at this point you will save yourself a lot of aggravation by buying a repair manual for your Civic. That will give you a step by step breakdown of removing the dash in the most efficient (and least damaging) way possible. You r dealer should have a repair manual available for purchase or if not you can try ebay or amazon.com. It's a long shot possibility that your local library will stock the Chilton's for your Civic but where it's a 2007 I doubt it. Good luck.