How to build a sturdy picnic table
Wood: 45 meters (150ft) of 100mm x 50mm (2"x 4") wood.
This amount includes the template and also allows for a bit of wastage.
Bolts: 16 galvanized coach/carriage bolts 10mm (3/8") thick by 110mm (4 3/8") long, or long enough to go through two thicknesses of wood plus enough to accommodate the nuts.
Also 16 nuts and washers to suit.
Nails: About a hundred 90mm (3 1/2") long galvanized flat-head nails.
Note: If you prefer screws - then do it.
You will also need 1800mm (6ft) of metal strap and a handful of 30mm (1 1/4") flat-head nails for the template.
The template can be a handy, time-saving device if you intend to make a number of picnic tables, as the template only has to be made once for any amount of tables.
HOWEVER - for a one-off, and for the more experienced DIYer, it is probably better to forgo the template and just go by the plans for side-frame layout.
Note about the wood:
Use a dressed wood (smooth, planed, surfaced) that is suitable for outside use.
The actual thickness and width of the wood will be less than the nominal size or the size that you call the wood.
For example: A piece of 100mm x 50mm (2"x 4") wood, when dressed (made smooth) will actually be more like 90mm x 45mm (1 1/2"x 3 1/2').
However, that is not going to effect the overall dimensions of the project.
Note: The metric (mm) wood sizes given are Australasian standards and the imperial (inch) wood sizes given are North American standards - hence, they do not match.