I am new here, I just recieved my HE and I am struggling with the learning curve. A lot of information and maybe I didn't choose the best starting point... So I hope you can help!
I have an Itead wifi switch (IM160426001) connected to my garage door, that I controle with the ewelink app. I would like to add this to my HE, but I have no clue where to start.
Welcome to the community! I agree, that is not the best place to start given the learning curve. I would start with devices that are natively supported. This is the best way to get your feet wet and get a better feel for it. Also, if you haven't already, start here: Hubitat Elevation Documentation - Hubitat Documentation
There are a couple of custom drivers and apps written for Sonoff but I have no idea if they will work for your device. But, if it will work for you, you will need to install a custom driver and/or app. Once you are ready to tackle this one do a forum search for Sonoff and we'll go from there.
Gday mate. Yes the HE is a lot to take in initially but once you get into it, it will get easier
In relation to getting your specific device into HE i'd take a look at the below link for the custom community HE driver. You will however need to flash your device to use another firmware such as Tasmota but you can find plenty of online videos on how to do that by opening it up and using the UART flash method.
Nicely done, sir. Now you are going to be faced with the rabbit hole and how deep does it go. Once you start to get comfortable you begin to realize all the things you can do that you probably never planned on. It gets really fun and exciting and expensive.