Hey Tiago, I will post some screens here for you:
First of all, the directory called OS39 where the BoingBag packs are unpacked (the boingbag.info files MUST also be in this directory, otherwise they will not be found).
Now simply follow the screens, in my case, the BoingBag's are unpacked under OS39, so click on it.
Now chose the BoingBag you want to install.
And finally click on installation.
Hope this helps.