The best way to get the pins in is to use a flat-head screwdriver to carefully push or pry open the clips, then insert each pin one at a time. Start with one clip and then work around the edges of the panel until all the pins are installed. Take your time, and ensure that each pin is properly seated before moving on to the next one. To increase flexibility, you can try gently bending the pins back and forth before inserting them. Don't try to push the pins through both points at one time; start by inserting them into one piece first, then move on to the other. If you plan on disassembling once the season is over, keep the pins in the upper points to save time next year. Additionally, assembling the pins in warmer temperatures makes them less brittle and less likely to break.