Good Afternoon

There are two hoops of elastic at either end of the sun canopy - these hook in behind the knuckles of the bar that goes over the carseat (the carry handle/roll bar). Once you've hooked them in (it is fiddly, but possible) you can then tuck the rest of the fabric in between the plastic at the back of the carseat and the carseat fabric.

If you can't do it, pop it into a local retailer and ask them to give you a hand.