In below picture show case was designed by using Aluminium T Strips. If you zoom-in then you can observe that.
T shaped Aluminium strips will be fixed in wall.
Once Strips are fixed, Aluminium brackets will be placed in T shaped Aluminium strips.
Glass will be placed on top of two brackets.
Carpenters will add plywood and sun-mica sheets outside of the showcase. You can use different good designs to improve appearance
Caution: For all the glasses which you are using in show case ask vendor to remove sharpness in the edges.
Good company for showcase brackets:
You can get this bracktes in 6 inch and 7 inch sizes
Another showcase design
Showcase under construction: