default admin password stored in mysql

Hello, total newbie to WordPress here.
The initial installation was a breeze, good job you guys. However, I’m a bit stumped on the customization – wp-includes.php the main place to do this? Also, I can’t login as admin – what is the default password? I confess to not remembering it if I had to enter one, but I’ve tried all the ones I’m using lately and none of them work.