Making a quilt

I am first going to include a disclaimer with this in case anyone might see it in the future. DISCLAIMER: I am not an expert or professional quilter in any way shape or form. The methods I will show are the way I have learned to do things and what works best for me, it is by no means the only way to put a quilt together.

That being said let us begin.

This is a quilt I am currently working on and I want to put a rectangle running the length of the top so that it will "finish" the center part of the quilt. As you can see in this picture I have already sewn two rectangles running the length of the sides. I did this using a 4x18 rectangle although I cut the measurement back to 16 inches and used two rectangles with the seam in the middle.

Here is another picture of the bottom.

These are the tools I am using: A cutting mat, 4x18 rectangle, and a rotary cutter. I used an 8 inch square for the squares in the middle.