If you search using Google using the terms "root. Z981" there is a ton of information. Watch some of the YouTube videos to get a visual idea, but the forums provide the details. XDA is always good. Also, I registered as a Developer with ZTE, using their website on China. Tons of useful help there, but it's handy to have translations set up. I've even simply requested ROM's, etc., and found them cooperative. I've been at this for decades. Just ask the people who wrote the code, or created the hardware (bypass sales!!).
You should have a clear idea of why you want to root any Android. If it is learning that you are after, you should invest $10 or whatever and sign up for an on-sale Udemy or some online university courses. Learn it in a way that gives you a future. I started rounding up 'hackers' clear back in the 1980's, as I have been running banks, universities, all sorts of very large computer departments. The serious ones now do things like be the CIO of Yahoo. Another owns the largest production company in Romania; he recently sent me photos of his guitar shaped swimming pool, and his beautiful wife and two daughters! See, he remembered all my stressing WTF is really important in life ;-)
I'm old now. Mind gone to mush. So I simply tell the manufacturers what the World (me!) Would like. The good ones love making us happy, if you're polite, communicate clearly, using the methodology they prefer. Learn to write. I ramble too much. 3 damn strokes. State the problem: what you need and why. Read everything. Take online courses. Get certifications. That way, you're learning in an organized manner. It quicker.
ZTE is encouraging in its attitude shift because on their side, our Han speaking compatriots, just as everywhere else, they are finding the best future employees are the ones asking the exact questions you did. I love it!
Sorry for carrying on a bit, peoples! MReedB