now we need to add the final piece of wood, the one that will support the tiles. Manufacturer's documentation specifies what size and spacing you should use... I suggest you stick to it obviously !!
The length of these pieces of wood comes in 4 meters, have the seems to be on the top of on one of the large beams. It a good idea to draw the position of each piece of wood with a chalked thread. don't bother cutting the beam at the right length, make just sure they overhang form the roof.