I recently rebuilt our garden decking, as when we moved in it was old and rotten.
In the first section I cleared the area, built a timber frame (painted all the ends / joins with wood preserve) and sat the legs onto concrete blocks.
We laid the decking boards down, and fixed them a screw width apart.
Finally, we painted the whole area with a wood stain / preserver.
In the second section, I continued with a raised deck onto the old flowerbed. Complete with steps and wood preserve.
I am not a trained professional, just sharing my building experiences.
Tools used:
Parkside Chop / Mitre Saw
Makita Jigsaw
Makita Hammer Drill
Hand Saw
Bosch Circular Saw
Decking boards, Timber and Screws bought from Wickes.