Chosen Solution
I bought my first smartphone yesterday, I used to only have a landline. I got the I PHone 7 plus. I was using it yesterday then when I woke up this morning it would not turn on.
this means that the battery is dead. plug it into a charger and wait until it turns on. it should show the battery percentage in the top right corner, along with a little icon.
I would take it back to the store under warranty.
