thanks for your interest in translating to Brazilian Portuguese.
Please find the new wiki page here about translation: https://wiki.openpetra.org/index.php?title=Documentation_for_Translators.
We are not using Pootle anymore, but Weblate. You don't need to install anything, just create an account at https://weblate.openpetra.org/
On the other hand: perhaps you should better wait until there is a stable version of OpenPetra, before you start translating. Are you considering to use OpenPetra for production use?
The project is at a strange stage at the moment. I have not had much time to post about current progress and goals. Just to say this: for TBits.net, we want to move from the Winforms client to web browser based client, before we go live with a hosted OpenPetra.
hope this helps.
Feel free to introduce yourself at https://forum.openpetra.org/c/developer-area/people
All the best,