create concrete patio with arc shape

[KilgoreRemod]

 

I am attempting to draw a new deck on an existing house.  The wood deck is exactly as I want it, but there is an existing concrete patio at the back door exit, shown by the shaded area.

First, how do I create a concrete patio?

Second, how do I make it have an arc shape?

The concrete will be at the same height as the new deck, top of deck at top of slab/floor level.

Third, is there a training video series I can refer to that will assist me in not feeling like such a moron when it comes to simple things like this?  I have scanned through many videos, all are well detailed in everything except what I need to know, and I cannot find what I am looking for in the help manual or the forums.

[KilgoreRemod]

I have shaded the area using poly lines simply to delineate it, but cannot find a way to transform that area into a concrete pad.

[solver]

Slab tool, or ...