Re: updating, confused

While an Info manual is still missing for BBDB 3, most of your
questions are addressed in README.

> Now, in gnus, looking at a message, typing : gets me the bbdb buffer if
> the sender already has an entry.
> 
> But, if there is no entry, I don't see anything.  I used to create
> entries that way.

In Gnus : is bound to bbdb-mua-display-sender.  This works without
or with a prefix.  And what happens exactly depends on the user
variable bbdb-mua-update-interactive-p.

From what I understand, you might want to bind
bbdb-mua-update-interactive-p to '(query . create).

See README.

> Typing ;, to create an entry and pull up notes (which used to work and
> still seems to be documented to do that), doesn't do anything.

; is boumd to bbdb-mua-edit-field-sender, see its doc string.

>   automatically display the record of the sender

Use bbdb-mua-auto-update-init  (see README)

>   create a record if I type :
>   not create records without my request

All these things can be configured individually.

> I have verified that
> 
>   bbdb-mua-pop-up is t
> 
> but feel like I must be missing something.

BBDB needs to know which MUA(s) it should hook into,
which is the job of bbdb-mua-auto-update-init.

Roland