'Des' does mean 'some', but it is often used where English uses nothing at all. For example, where English would simply say 'There are people here', French would say 'Il y a des gens ici'. French doesn't have a 'zero article' ( i.e. just saying 'people' or 'books' with nothing before it) in the way that English does. You have to put something before every French noun, so when the noun is plural and indefinite, English just says 'books', whereas French has to say 'des livres'.
'Quelques' also translates as 'some', but it means 'some' in the sense of 'a few' or 'several'. 'J'ai lu quelques livres' = 'I read a couple of/ a few/several/ books.'
I hope that helps.