Gday everyone,
I'm currently building a greenhouse and picked up this polycarbonate sheet.

i was going to secure it with these, however, I didn't realise how thick it was

but I'm guessing that won't work, as I was expecting the sheets to be like this:

so has anyone used the thick SunTuf stuff? Should I return it and find the thin stuff?
If I stick with the thick stuff, how do I secure it? Screws?
Any advice would be appreciated.
Thanks in advance