Dear Something About FMCG:
Frankly, we do not understand your first question. The FMCG companies typically manufacture and market their own goods. However, depending on what a particular FMCG company produces, it would need the raw materials for manufacturing, and the producers of such materials would market to the FMCG company. For example, the produces of tomato sauce may purchase tomatoes from another vendor, so the tomato producer would market to the sauce making company.
Civil engineering has no obvious and direct relevance to the FMCG companies, insofar as the core business of manufacturing and marketing consumer goods. However, civil engineering may be of some limited value to planning and building manufacturing plants.
Anything you need to know about the FMCG companies - at least what is publicly available - is available on their individual websites. Their websites also include employment opportunities. You may wish to visit the
FMCG Brand Directory for further information.