Question about external hard drive's

Hi, sorry if this is in the wrong forum. Anyways, I recently bought a WD My Book essential edition 1 TB external hard drive. I plugged it in and it seems to be working fine, Time Machine has been doing back up's to it every hour. My question is that I was trying to figure out how to drag and drop files to it. I have a large itunes collection of music and movies. I like to rip my dvd's to my mac and format them to mp4. My goal is to put them all on the external hard drive without using space on my Macbooks internal hard drive. But I can't seem to figure out how to manually put them on their. Thanks for the help and again sorry if this is in the wrong forum.

This is because of the format of the drive. Read this and there are links in there for apps you can use to access files on a HD formatted in NTFS. Good luck.