Use shortcut "f" for full size.
Use shortcut "5" for viewing frame.
Use "alt" and left mouse click drag to rotate the light.
Below is a nice sample with low poly modeling, quads mostly as well.
Use middle mouse to zoom in and out.
To embedd models you find yourself on sketchfab that you think is good, use the sketchfab sites embedd code, set size to fixed and 600x600.
then use the Iframe editor icon in this forum and chose edit html, and set the scaling to 800x800.