Integrating my custom smart tv command into Domoticz

Hi,
I’m currently choosing my domotic system (between home-assistant, Domoticz and Openhab)
I juste reverse enginered my not so smart TV, an Haier V300S, I have all the post request to change channel and everythings.
Now I want to wire up everything with an Alexa Integration.
How I to do That? Do I need to write a plugin? Can write it in Javascript? How my Smart Home Alexa skill will discover my Smart Tv and have all the command like change channel without opening a skill?

Thank for you help.

A good starting point for answers to your questions is the documentation: