The most important step is to ensure that the windows are as tightly closed as they can be using the orange ropes. These can be tied down instead of just relying on the weights to hold the frame in place. If you are unable to tie the rope down due to the length you can make them longer with other ropes or by using zip ties.
Tying the windows down is followed by locking the window frame fully by inserting a zip tie through the hole in the frame and around the bar that sits right below the window frame as can be seen in the picture below. This is the most reliable frame to prevent any movement in the window frame, but can be difficult to install. Feel around with your zip tie through the middle bar of the window frame until it goes through the hole. The location can be seen in the picture below
Also important is to remove the cilinders from the automatic arms. These will try to push the window open and can potentially break if the window is locked down with a zip tie. Removing these is very easy: just take the clip out that connects the two rods together and then screw the cilinder out of the frame.
Something else that needs to be done is to remove any objects around the greenhouse that can be blown against the windows. This can easily break a window and throw the glass throughout the grow beds. The large beach umbrellas from the restaurant terrace for example can be moved around by strong winds. Also be on the lookout for anything above the greenhouse like sunscreen weights or open windows.