Hi Yvette, and welcome.
By 200 inches square I presume you mean the quilt should have approx. 200 inch-sized squares in it, and not, as Mia seems to think, a 200 x 200 " quilt (an altogether different challenge
). You found the way to open a picture and go to the regular pattern dialog, so as an example, let's see what happens if I do this:
As you can see I chose 1" squares, 13 x 17 = 221 squares in total, and when I click 'OK' I get:
The next step would be for you to judge if this is enough detail, if you like the number of squares/size of the design, etc. If not, just go to the Menu 'File' -> 'New' and try again, with different settings.
And if you do get something you like, the next step again depends on the way you want to do things. You may want to try to reduce the number of shades in the image, so you can use a limited selection of fabrics: menu 'Edit' -> 'Reduce Number of Colors'. Or you may want to add extra detail in certain by 'cutting up' individual squares. Or you could just print the design as-is and use it to rummage through you fabric stash (I presume you have one of those).
Let us know how you get on and if you need any more direction.
Best wishes,
Arnout