BuddyPress.org

I am struggling with the customization of the register page. I need to put the labels and desriptions on the right place cause some of them are messed up. I understand that the page is filled on a loop at register.php. But how can I chance whats in the loop?

Any docs for that?
I only found that old post which shows that I am not the only one with this issue.
https://buddypress.org/support/topic/registration-page-styling/