Hi, I'm Nathan.Sorry to hear that you're having trouble with this but I'll do my best to help you.
Congrats on getting a fire stick, they are a great device for streaming online content to your tv.
#1) The fire tv is a singular device, it can service only 1 tv, it plugs into the hdmi port on the back/side of the tv, along with a usb or power cable, from there it interfaces with your home wifi network for internet signals.
#2) The fire stick and dvd can be connected at the same time, typically each would have its own hdmi port, so you may have the directv box on hdmi1 on the tv, the dvd on hdmi2, and firestick on hdmi3, for example. To switch between them, use the SOURCE or INPUT button on your tv (not dtv) remote, pressing it repeatedly as needed to cycle through the different input modes to get to the desired device (ie: hdmi3 for firestick, in this example).
If you have any other questions, just let me know. Otherwise, please take a moment to rate my service using the stars at the top of the page; hopefully I have earned 5 Stars. I also invite you to contact me directly with any future support needs at http://bit.ly/1QwLxGh and ask for Nathan.
Thank you, ***** ***** a nice day,
Do you need more help with this?