So in the basic carbide create guide it looks as if the boolean option is just supposed to show up when you make a shape, or two shapes. However I cannot find any option for booleans. Can someone let me know what I am doing wrong here?

I am trying to round out the edges on some .4" thick rectangles.

so I guess that is one of the issues, I cannot select two shapes at once apparently… normally this would be done by holding shift while selecting (in other 3D programs at least).

I have attached an image of the round out I am trying to achieve.

You want to draw that differently — use two rectangles creating a notch, then draw the rounding circle, then union.

Alternately, draw a square at the corner, then the circle, then subtract the circle from the square, then subtract the notched square from the rectangle.