Usually, we need some idea of what we are trying to make before construction begins. This conceptual starting point might be in the form of a drawing, a recipe, or a computer program, for example. A drawing can show in great detail what the finished object should look like, while a recipe provides a series of instructions which may not fully describe the end result, only the process for making it. Thus, if we are making a cake from a recipe, the final outcome may be affected by a variety of environmental influences - the quality of the ingredients we use, the shape of the cake tin, and the accuracy of the oven's temperature control can all influence the end result.

Then we need a supply of appropriate raw materials. Usually these materials will need weighing, measuring, shaping or cutting to definitive sizes to provide the components for what we are making.

The components are assembled and the finished object - depending on what it is - switched on, tested, tuned up and put into operation: we wouldn't usually expect full function before completion.

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