I think I've found both of your tickets, which, when logged in, I can see. So the question there is - what email account is your bitcard associated with? Your gmail account? (Mine is connected to my cpan account which has made things easier when changing email addresses - just had to point the cpan.org bounce to the new email address and everything continued to work as before.) Just double check that. (Since you've not posted identifying information, I won't post any, either.)

As to how to interact - just reply to the emails in your email client (whether that's gmail or your IMAP client or whatever). As long as you leave the subject alone, it should get routed correctly. You don't need to sign up for the p5p mailing list, though I've found it handy in the past. (I'm currently sitting with 885 unread emails in that folder, so, um, I'm a bit behind.)

And I've not been able to figure out how emails in the list work. There's something asynchronous going on - how can someone respond to your email prior to moderation accepting it so that they can receive it and respond? :) I've seen responses to others' emails where I don't receive the original post for a day or three after I receive the response. Time travel does exist, at least on the p5p mailing list!