My first solar cooker

I have been meaning to make a solar cooker for several years, and have been looking at designs and YouTube presentations of different styles.  Encouraged by an ad recently designating Father's Day weekend as solar cooking day, I started putting some things together.
My idea was to use an old charcoal grill and a Dutch oven somehow.

I made some sketches, and took some measurements, and this weekend, a week late for solar cooking day, I cooked my first items.
I decided to use the box within a box with insulation.  Having some cardboard around the house, I fashioned a 14" square, 12" high, around a 10" diameter Dutch oven.  I used a 14" square picture frame with glass for the lid.

Insulation tucked in around the outside of the box is some fiberglass insulation I had in the basement.
I found a picture frame, 14"x14" with glass, that went on top of the box.

My first attempt was to bake two apples, cored, for one hour.  That was not enough time.  We were out that afternoon, and my second attempt with a sliced cored apple was mildly successful.
Oven Temperature remained 150 deg.F throughout.
My next phase of cooking will to be improve the efficiency of this oven.  I read that I should be able to get 250 to 300 degrees in the oven.
Some improvements to make:
     -use a top with a more sealed connection to the box.  There are gaps in the present configuration.
     -Try to track the sun more.  The best heating was when the sun was high in the sky.

Lessons Learned:  Solar oven cooking has a different time frame, on the order of hours.
I have a lot to learn, and hopefully will be able to improve the product and/or build alternative designs every weekend from now until the end of the summer, on the weekends.