Vinyl Siding Installation Question

[Chris LaBoda]

I will be installing 7 new windows, 1 door and vinyl siding on my porch. The old siding will be removed and in its place 1/2 OSB sheathing then Tyvek, then vinyl siding. In some places the existing siding sits about a 1/4" back from the edge on the concrete slab up to 1" back. The inside of the porch is gutted down to the studs. I have never done siding before but my neighbor a retired carpenter has.

The question is how to start the first row of siding with the exterior walls sitting back up to a 1"? The first two walls I can bring out the sheathing out where it meets the slab. The last wall doesn't look that easy?
Suggestions?

 

[Snoonyb]

The unevenness is difficult, aesthetically, to address, and will remain, in some fashion, however when they are addressed, a "Z" BAR flashing is a common answer; https://www.google.com/search?client=safari&rls=en&q=z+bar+flashing+dimensions&ie=UTF-8&oe=UTF-8

 

[Chris LaBoda]

The unevenness is difficult, aesthetically, to address, and will remain, in some fashion, however when they are addressed, a "Z" BAR flashing is a common answer; https://www.google.com/search?client=safari&rls=en&q=z+bar+flashing+dimensions&ie=UTF-8&oe=UTF-8

Great idea.
Thanks!