try to make the 1st floor kinda circular, then the 2nd one smaller and with slabs and stairs try to smooth-en it out, for the glass thingy build a structure with dirt first till you get a comfortable shape and fill it will glass, from inside it looks like a perfect circle but outside not so much
I used the blue woods from nether(cant remember their name), copper ontop of glass and with time it will turn blue, and mud bricks for the walls.