Organic synthesis: describe question

Methyl salicylate, $\ce{HOC6H4COOCH3}$, is hydrolysed with aqueous sodium hydroxide to form sodium salicylate, $\ce{NaOOC-C6H4-OH}$. The sodium salicylate is then acidified to form salicylic acid, $\ce{HOOC-C6H4-OH}$. Salicylic acid is converted to aspirin, $\ce{CH3COO-C6H4-COOH}$, by reaction with ethanoic anhydride.

Describe the type of reaction and the reagents and conditions for each of the three steps in this synthesis of aspirin. In your answer, state the functional group present in methyl salicylate that reacts in the first step, and identify one possible by-product of the final step.