Composite decking is very expensive. Always plan ahead to reduce wasted material. The field deck in this picture is 24' wide with an additional 6" picture frame border. In this case we are staggering the butt joints every 4'. We added double 2x10 joists to support the seams. An alternative is to use a division board and create 2 decking fields.
Make sure you level both joists to the same height and fasten with 4 screws every 12" to support the composite butt joints.
Leveling the joists is very important to keep the butt joints at the same height. Be sure to use 2 clips on the double joist when using a hidden fasting system. Make sure to gap the butt joint at least 1/8".
To install composite decking with a hidden fastening system start at the house by face screwing the first board. Next screw a hidden fastener clip into the groove on top of each joist. Then slide the groove of the next board into the clips and tighten with a rubber mallet.
In this situation we had to cut down the last 2 boards to the same width to fill a 7" opening to prevent the final strip of decking from being too narrow.
Notch your composite decking material around rail posts. Make sure to leave at least an 1/8" gap for thermal expansion. In this case we will be using a rail sleeve and base trim that will cover the gaps.