Here is an online youtube to mp3 converter which you can use to download the tne you need to your computer and after that I am pretty sure that you'll figure out how to transfer the mp3 file to your smartphone.
You can download videos from youtube using a program from dvdvideosoft... once they have finished downloading, you can copy/paste them to your phone
You need to download youtube downloader,it saves your vids so you can keep them on your pc,and then transfer.
I connect my usb cable laptop & to my phono also press pc suite but no means.