Thanks for your help. I figured it out. This is what I did;
1. used ext wall for porch.
2. changed ext wall into railing, by taping the wall to open wall specs, open rail style tab and creating railing of my choice.
3. Place a door on one of the walls, of course it was a doorway by default, change to swinging door and style, also the height as well.
4. created a screened wall by placing a wall just inside of my now railing. Do not let it touch the railing or you will loose it. Click on the wall and create a new wall called "screen wall", changed the thickness to 3/32 so it is easier to handle. I moved the screen wall to just inside the rail wall. Do not let it touch or you will loose the rail wall. I adjusted to screen material to lighter properties.
In the south we have porches that are screened in because of the bugs. I hope this will help others.