You have the IDA View and Hex View right. When on IDA View you select an instruction you can see the instruction selected in Hex View as well. However, if you select a "data instruction" like "Format = dword ptr -10h" which is a stack variable, you don't see it in the hex view. It doesn't select the bytes corresponding to the variable definition. I mean I know the variable is going to be there in memory but somewhere on the hex view should tell me "hey allocate this stack variable" but it doesn't.
It's probably obvious by now, I'm a beginner in reverse engineering, I've been reading the book from http://beginners.re/ . While I do know some assembly and have been able to reverse simple things, I have these knowledge gaps I'd like to fill. Thank you!