Root Boot Animations Help?


So I just downloaded a splash screen... that was easy but boot animation on the other hand... how do I do that? I ready the instructions on xda, but I still don't understand...?

They said: Boot animations are replaced by finding your current one in a file explorer (in CyanogenMod its in system\media in Virtuous and Sense ROMs system\customize\resource) and overwriting it with the new one. Have to keep the same file name as the one you're replacing.

I found my current one and i downloaded the one I want. Now what? I tried replacing it through File Manager but it won't let me move the file out of my sd card. Am I supposed to do this on my computer? If so, how? Thanks