BuddyPress.org

If you totally want to restyle the buddypress theme then you should indeed just copy the bp-sn-parent folder, give the copy a new name and start editing that. Though, it’s recommended that if you just want small changes, to build a child theme.

You can find a guide here on building child themes.

https://codex.buddypress.org/how-to-guides/building-a-buddypress-child-theme/