Any thoughts gratefully received

I moved a greenhouse from an allotment where it had been
vandalized to a concrete pad next to my house.
This involved dismantling it and re-erecting it - without
the original instructions.

Don't attempt glasswork if it is windy. Handle the glass
with gloves if possible - its often a bit splintery round the
edges.

Get the site level and flat before you do anything else. Your
greenhouse probably has a bottom frame that bolts to the ground
before you build anything else. After bolting make sure its
level by shimming or something. Build the frame then
make sure its square, true etc before putting the glass in.

I didn't do this myself and my greenhouse has a slight assymetry
in that the gutters are about 2 degrees out from the horizontal.
In one the water flows towards where I want it, and in the other
it doesn't. Short of taking all the glass out and starting again
I will have to put up with it.

Do not attempt to cut glass to size. If you need a particular
triangular shape or a smaller rectangular piece, make a paper
template, take it to a glass merchant and it will be cut to size
at no extra cost. Horticultural glass is unimaginably cheap anyway.
Trying to cut it yourself rarely produces pieces the wanted shape,
takes time and effort and is slightly dangerous