Default [Q] How to TWRP backup with YDSS.CN?

Newbie here.
My bro in law bought a lenovo s920 for my nephew and it is rooted (they don't even know what this actually means). The sd card would not show up but after faffing around with it I got it working somehow by restarting the phone. Anyway, thought I better back this thing up just in case it ever needed factory resetting and after hearing that you should not factory reset a rooted phone the usual way, I downloaded the TWRP app.
Problem here is, after following the procedure where I've checked what needs backing then slide the backup button and input a name for the saved file, the phone switches off and the next screen appears is in chinese with a ydss.cn logo. (I've attached photos).

Here is where I don't know which selection to make. First time I tried I just picked the first one and this just restarts the phone, but I don't think the backup is successful because I can't find the TWRP folder anywhere.

Anyone has any idea what the procedure is with this ydss.cn?

I've never rooted a phone before and just wanted to back this up so I can just restore it easily.

Any advice would be most appreciated

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