To add Buddypress to your WordPress site you will want to visit your dashboard and find the plug-Ins tab on the left Navigation. Once you hover over that choose Add New from the options.

Next you will want to type in Buddypress to the search box.

This will bring several Buddypress related items, but the first should be Buddypress itself. Choose the instal option and follow the prompt to activate the plug-in.

Once you have activated the plug-in you can find access to the settings from the settings tab in the left navigation:

Configure these settings and enjoy!
For more info and support go to:
http://buddypress.org/