Start with the basics, and work back.
there is nothing complicated about any greenhouse.
No idea what yours is but I would guess you can find these parts.
The long bits will be the ridge, 2 x eaves, and 2 x base runners.The the eaves will probably have a gutter channel on them.
You will have 4 corner uprights that will all be the same length, and probably angled profile. Then 6 x T profile section all the same length.These are the side runners.
The 4 longer T profiles will be your end panels.The door will fit into one of these.
Any smaller angled profile is either a brace or a crop bar.Braces on the sides will be diagonal.
Then its just a matter of marrying up the holes to piece it together.
Nothing to it really, generally takes a couple of hours to get the frame up together.
If you are cutting glass to fit yourself, warm it in the sun if you can, as old glass cracks easily when cold.