okay, thanks for that. I found one article that might help but the video playback part is still a mystery to me

Hi, I have purchased the pi B+ and was able to boot it up. Aside from that, i'm unsure where to start next:) I am trying to use the pi to use as an alarm. When the sensor triggers the alarm, the pi will play back a video. Any suggestions as to where I should focus my attention? thanks in advance, -t...