the word 'many' can function as an adjective meaning 'large in number; numerous'. When used as an adjective, 'many' often appears before a noun, e.g. 'Many students were present at the rally'. However, when the words 'so' or 'too' are present, 'many' is often placed after the noun, e.g. 'There were too many people at the event'.
1.'He spent many hours preparing for the exam.'
2.'We had to use many cups of sugar for the cake.'
3.'The library had many old books.'
it is important to note that 'many' should not be confused with 'much' when used as an adjective; 'much' is used to describe large quantity whereas 'many' is used to describe large number. Many is usually used with countable nouns and much is ised with uncountable nouns.