I reccomend going to the iTools Discord and following directions, links and steps through there since those are official links from iTools themselves and stuff like that. Check pinned of a few of the discord channels and most of them have instructions. I have a post on my reddit profile from a while back in this sub that goes into a bit more detail and explains it all a bit more. All of the info in that post is still relevant and has been updated as far as I can tell.
Here is their website where you can find where to purchase the devices and all that stuff. A few different devices there, I personally recommend the regular iToolsBT if your looking for something compact that doesn’t need to be plugged into your phone and won’t be visible unless you take it out of your pocket or whatever. The iToolsBT 2.0 is also pretty good, but thats what I’d prefer to use at home because you simply just look weird walking around anywhere else with a odd shaped plastic joystick in your hand... The 2.0 is really good for using the shortcut buttons for shundo sniping though if thats your thing.