Last I knew, the SPF side curtains are individually fitted to the car at the factory. The bag for the side curtains should have "your" car number written on the inside flap.
Front pin goes in first (just a litle ways, until the rear pin contacts the ferrule). Then set the rear pin over the ferrule and pull the top of the side curtain slightly inwards while pulling down on the base. The flap faces outwards. You may want to lubricate the pins just a bit.
If you can have someone show you how to do it, it's a piece of cake.
Now, getting in and out of the car with a top on - THAT takes some moves
