Looks like a straight forward build.
Step 1 cut out the base of your glass house; either a hex or octagon, or even a square of the desired size.
Step 2 cut out 6 or 8 or 4 identical isosceles trapezoids (whoa ...geometry timewarp there) depending on the style you choose out of stiff plastic, clear styrene, top loader card sleeves, etc of choice. They have to be identical. The length of the shorter parallel edge = the length of one of the sides of your chosen base.
Step 3 Start by attaching two isosceles trapezoids to the base next to each other and attach the angled sides together. Continue around the base until you have gone all around. Add some vertical support framing along where the angled sides attach; this will hide the messy joints.
Step 4 The roof is the same shape as your base but with the length of the edges equal to or greater than the length of the longer parallel edge of the isosceles trapezoid. Greater if you want a roof overhang.
Hope that helps.