BuddyPress.org

That would be wpmu from here: https://mu.wordpress.org/download/

And bp from here: https://buddypress.org/download/

Those two would be the latest official releases. Where did you put bp? That version of bp should go in /mu-plugins. You should have a bunch of files like bp-core.php, bp-<whatever>.php in that dir and also a bunch of subdirs like /mu-plugins/bp-activity, /mu-plugins/bp-<whatever>

That what you have running?