[Q] installing CM 12 lollipop rom on s3 neo topic

Hi can someone tell me how to install lollipop rom on my s3 neo.Currently it is working on 4.4.4 kitkat I am using I9300 model.
I have rooted my my phone using Odin and checked with root checker and it is showing that my phone has root access.But while wiping the data and installing from zip file in recovery mode it is showing "signature verification failed"