How to install an clean version of android on Lenovo A936

Hi,
I wonder if anyone can point me towards a tutorial for novices showing a step by step method of removing my existing android and replacing with an official version. I am afraid I don't have a clue on where to obtain the "good" uk version of android or how to change it from my existing version - I am sure the existing one has bloatware and probably malware installed by the Chinese retailer.
My phone has 4.4.4 installed and I am quite happy to have the same Kitkat but would obviously prefer a more recent version if this is possible.
Many thanks in anticipation for any help offered.
Regards,
John.

Hi,
I have not received any help to my request, I expect this forum is really for "techy" people so I was wondering if there might be an Android forum that is more geared to novices - any suggestions gratefully received.
John.