Need help setting up a greenhouse kit/how to do base/floor.

Would like some help from those that have already setup and own a greenhouse or have experience setting up a greenhouse base/flooring. I own a Canadian Tire 6' x 8' plastic greenhouse I got around a decade ago. I'm looking to build a greenhouse in the backyard but the thing that has stopped me all this time is how to do the base.

I'm not sure if the greenhouse came with a base kit. I paid like $499 on sale then for it. Have not opened it yet. I plan on using this 12" x 12" https://www.homedepot.ca/en/home/p.natu ... 20661.html but not sure if it is a good idea. My biggest worry is the greenhouse being blown off it's base from a windstorm. In my area (Toronto, GTA North) I have experienced just shy of 100kph winds before howling outside. The last thing I want is the greenhouse to fly away. I thought about pouring a concreate base but I have no experience doing that and also I want to do this as economically as possible.

Thank you in advance for any help. I hope this thread will also help many others in the same situation and help them out with the setup as well.


EDIT:

My greenhouse looks something like this https://www.amazon.com/Rion-HG7012-EcoG ... B00M5J2B88 It can if I recall right it can be extended length wise if you have more units.