How to flash Mi4c weekly ROM using TWRP?

The European Mi4c weekly ROM was released today, and according to the website I should flash the ROM using TWRP. I've managed to root and install TWRP on my phone, but what next? There weren't really any clear instructions over there, and I've never done any of this before and so I don't wanna risk bricking my phone.

So, how do I install the ROM? Do I need to wipe my caches or do a factory reset? Where do I place the ROM for installation?

Thanks guys. Sorry for such an obvious question.