Friend Request and imprt friends from FB

Hi,
Thank you for asking.
1. In Dashboard->BuddyPress settings page please make sure that Friend connection component is enabled.
2. Have you registered multiple users? If no, Please try registering atleast one other user.
Now,You can visit members directory or the profile of the user and if you are logged in, you will see the button to send friends request.

Please do take a look at these links to see how BuddyPress works
https://codex.buddypress.org/buddypress-components-and-features/
and
https://codex.buddypress.org/administrator-guide/

Hope that helps.