How do I get OpenHAB2 to work with my Alexa

Setup, Configuration and Use Beginners
2

You have several options: Official Alexa skill, hue emulator, …
In either way, you have to use the syntax definitions in
http://docs.openhab.org/addons/io/homekit/readme.html

Short example for the Alexa skill (after setting it up properly according to the instructions):

Your working switch from your items file:

Switch TestSwitch "My Test Switch" { your_binding="...." } becomes

Switch TestSwitch "My Test Switch" [ "Switchable" ] { your_binding="...." }

Then let Alexa search for new devices and you should be able to turn the light on and off via “Alexa, turn My Test Switch on” or “Alexa, turn My Test Switch off”