Look through old cupboards and family collections to find all the medals you can. Once you have found every medal or award, put them all out on a desk to assess whether you will require one shadow box or more, and in what sizes.
Once you have an idea of the space your pins and medals will occupy, go to your local crafts store and buy a shadow box. Make sure that your shadow box is a bit deeper than a regular picture frame in order to house all your items.
Along with buying the shadow box, also purchase a piece of thick velvet cloth to use for the background. The velvet cloth should preferably be dark in color in order to provide better contrast.
Lay out the medals and awards according to their sizes. Once you are satisfied with the formation, pin them to the background cloth. If a medal or award does not have a pin at the back, use a straight pin to attach it or stitch it to the background cloth with needle and thread. Wrap the velvet cloth around the backing piece and after making sure that nothing is crooked, fasten the backing to the shadow box.