Where to put the books and comics in V3.1 on casaOS.

Hi, I installed Ubooquity new on a RaspberryPi as software i downloaded from the casaOS-Appstore. Before the was a Ubooquity-folder in the app data section of casaOS. I guess that was under 2.x which I had running for some time on a RaspberryPi with casaOS too. Can anybody help me with this very simple question. I am not really a tech guy. Just enough patience and knowledge to install and run casaOS on my Raspberry Pi. Please help me.

Thanks in advance!

Lutz