Hi Xavier:
Welcome to Hyperbole use. To learn Hyperbole, try its builtin Demo, {C-h h d d} and look at the Hyperbole Manual. But for your BBDB question, this may explain enough, from the Hyperbole Manual, HyRolo Settings section:
If you use the Big Brother DataBase (BBDB) Emacs package to capture email addresses and store contact information, the rolo automatically works with it. If the BBDB package is loaded before HyRolo, then your bbdb-file of contacts is added as the second entry in hyrolo-file-list and will be searched automatically for any matches by the rolo find commands. Presently there is no support for editing BBDB entries, just finding them.
For finding matches within only BBDB, there are the commandshyrolo-bbdb-fgrep (string finding) and hyrolo-bbdb-grep (regular _expression_ finding). They may be bound to keys if desired.
-- Bob