Starting from the highest point on the downpipe fix the clips to the wall using rawlplugs and screws.
How to hang pvc pipe from gutters.
How to install pvc pipe for drainage.
In my wife s village near madang papua new guinea they always use pvc pipe for guttering on corrugated iron roofs.
1 1 2 x 8s screws should be sufficient to hold the clips and pipe in place securely.
Install the gutter and run your 1 5 downspout with 90 degree or 45 degree depending on your configuration.
A downspout would be very simple to make as well just simply glue in two end caps and a 3 x3 x1 5 tee to your 3 pvc pipe.
Begin at the very end of where the drainage will end and set the depth on the trencher to 16 inches.
Start from the location of the down spout on the gutter system and mark the desired path of the pvc drainage pipe on the ground using.
Space these around 4 to 5 ft 1200 to 1500mm apart.
Use your spirit level to ensure the downpipe is straight.