Beside , Besides
Beside is a preposition that means 'next to', 'at the side of'. Besides is a preposition that means 'in addition to' or 'apart from'. Besides is also an adverb that means 'in addition', 'also'.
You should sit beside your brother.
The cinema is beside the supermarket.
The film was too boring, besides being too long.
No one talked to her besides her mother.
The film was too boring. Besides, it was too long.
She works all day. Besides, she has to do the housework.