I really don’t understand how media players and remotes work, is there any place that i could read up on this or watch a video. I’ve read the general documentation but I’m still stuck. I’m trying to write scripts that will change the inputs on my fire tv and denon avr receiver
You need to do it in steps, so you can comprehend the setup.
Start by getting the denon amplifier integrated.
When you can control that with a card in the GUI, then look into controlling the fire tv.
Once you can control the two devices from the GUI, then make any scripts needed to link action you would like, which could be like to turn on the denon amplifier when a certain source is selected on the fire tv or whatever you come up with.
Last add the remote to HA with an integration and then link the remote buttons to the scripts and functions from the previous work with action calls.