Questions about USB hard drive

I have a Raspberry Pi2 with OSMC installed on an SD card. I use a wireless keyboard and have an externally powered usb hub. What I would like to do is put my movies and music on a usb hard drive so I can access them from my Pi. The movies are presently on a Windows 7 desktop in the MKV format. Now my questions: What is the easiest way to get these files from the desktop to the Pi? What should I format the hard drive with? Does MKV work with OSMC or do I need to convert them to something else? When format works best for audio files? I do have the codecs already installed. Thanks.

While from a performance view not the best, but the easiest is you format the drive to ntfs then you just can connect it to the Windows PC copy the movies over and then connect it to OSMC

While mkv is only a container the question would be which codec you use inside. Assuming you are using H264 that should work.