As an initial step, you need to activate this plugin: https://wordpress.org/extend/plugins/bp-template-pack/ to create the folders necessary to make BP play nice with your theme. I will say that it is still clunky at that point, and may need some massaging. If you aren’t comfortable tweaking CSS, you may be better served choosing a Buddypress Theme, rather than trying to get a WordPress theme to work.
The Devs are aware of this and are currently building Theme Compatibility right into the plugin: you can read more about that here: http://wpmu.org/coming-in-buddypress-1-7-compatibility-for-all-wordpress-themes/ You may want to wait for this if you are integrating into an established site and you don’t want to change themes.
