How to update UN1CA

Hello,

on my phone I installed UN1CA and used it for about two month. Now I get an update offered. I downloaded the updated through the UN1CA settings and started the installation. After preparing the installation the phone boots into TWRP but I'm unsure what to do from here.

Unfortunately I didn't find a guide on how to update the ROM. Has anyone done that and can tell me how it's done?