Esters are assembled by reacting a carboxylic acid with an alcohol with a concentrated sulfuric acid catalyst. The Alcohol makes up the "yl" bit of the name and the acid makes up the "anoate" bit. E.G. propanoic acid + ethanol ---> ethyl propanoate.
carboxylic acids are formed by the oxidation of a primary alcohol (an alcohol with the -OH group at the end) this is done using acidified potassium dichromate (K2Cr2O7- represented as [O] ) and heated under reflux.
e.g. propan-1-ol + [O] -----------------> Propanoic acid + Water