installing custom boot animation on moto g topic

Hi I'm new to this, came across a really cool ps1 boot animation and sound but don't know how to install it. I've just rooted my phone and on 4.4.4 and its a xt1039. I have both animation and sound zip files and I believe I have the latest unofficial twrp recovery manager via fastboot. Any help on how I can install it and would it be best for me to backup my ROM? It's stock no custom ROM on yet

Thanks