Registration page customization

You can put this in your child functions.php file.

add_action('bp_before_register_page','my_registration_instructions');

function my_registration_instructions() {
 echo 'put your instructions here';
}

However, if you dont like where it is placed on the page, then you’ll have to copy /kleo/buddypress/members/single/register.php to your child theme and add your text where you want it.