1. Download the .PO file as instructed (as you did)
2. Open the file using POEdit
3. Save it, so .MO file will be created.
4. Move both files (.PO and .MO) to folder wp-content/languages/ (if not exist, create it)
5. if you are using hebrew wordpress, make sure your files named: buddypress-he_IL.mo and buddypress-he_IL.po
If it still doesn’t work, make sure the language on your wp-config is set to be he_IL .
If still not so you gotta make some harsh change:
1. go to wp-content/buddypress/bp-core-functions.php
2. search for function named bp_core_load_buddypress_textdomain
3. give $mofile a value. set it to be ‘buddypress-he_IL.mo’, so it won’t get a dynamic value.
This is the worst case and it’s really not the right way to do it, but if all other fails, this should work. if it’s not working, make sure you named the files correctly and placed it on the correct folders.