The process is governed by a clear set of instructions or specifications. In some cases the final products are for immediate or local use, in others they are packaged for export. In the cell too there are production lines, in this case manufacturing new proteins of many different sorts. The messages from the cell's DNA act as a blueprint. This blueprint is interpreted by machines on a production line, which are called ribosomes, to assemble the correct sequence of amino acids.
Amino acids are the building blocks used to make proteins.
As in cities where products made in factories are used within the city, so the completed proteins are often for home consumption, but others may be exported outside the cell for use elsewhere. All manufacturing creates waste products , which need to be disposed of.