You can get the directions on the website I posted below. I am not sure about the heating for your particular greenhouse. I have a glass house heated by radiant hot water heat. I try and keep my temps in the 50's at night, mostly because it isn't economical in my case to keep it any higher. But this seems to work well for me, and i grow a variety of different plants.

Happy Growing!!!
Sarah

Here is a link that might be useful: Instruction Manual

Depending upon how far you are from an electrical outlet, a single 1500-watt electric heater will give you +13F in your particular gh "tent." If you have to use an extension cord, use 12-gauge -- to eliminate as much of the potential power loss as possible. Otherwise, your heater will only operate at about 75% capacity.

BTW -- the greatest difficulty you'll have at this time of year is regulating the high temps, not heating. You'll have to be especially vigilant about zipping and unzipping it in morning and evening.

A couple of hours in the morning at 45F (if outside temps dip to freezing) or so shouldn't hurt sensitive seedlings.

-Bruce

Thanks :-)
What am I supposed to do with the big black shade cloth? (is that even what it is?)

Big black shade cloth will go over the top in the summer. And you will appreciate having it. I purchased aluminet 70% shade cloth and positioned it in a way that provided the best coverage for the sides of the GH that seemed to get the most sun/heat. so it's not a perfect fit over the top, but more of the material is towards the south and west facing sides.