What is the pathway to get started at AR development?

Hello. I am Alejandro, i had researched about how to develop AR aplications and i found unity.

I did "the basics" course from unity learn, and then i wanted to start from the AR template, and “all the tutorials” like the entry said… but i ended really frustrated.

I just want to know where can i go for learn how to get involved on this. My final goal is develop Human Machine Interfaces (industrial aplications, like taqtile or innovae concepts)
I´m already a industrial programmer and i want to go beyond, but i have any experience at unity.

I readed a lot, but more i read, more confused i am.

¿Can someone give a pair of guidelines or a pathway on how & from where can i start to learn?

PD: I want to play whit my iphone until i will decide to get a AR device.

Thanks in advance.

To start I suggest guides on YouTube
Dilmer is a good source