If one thing is beside another, it is next to it or at the side of it

1. His mother sat beside him, clutching her handbag.
2. Beside the shed was a huge wire birdcage.

Besides means ‘in addition to’ or ‘as well as’.

3. What languages do you know besides Arabic and English?
4. Is there anything else wrong besides her heart?
5. The farm possessed three horses besides Clover.
6. Besides its own publications the works have handled many other magazines.

Besides can also be used as an adverb meaning ‘in addition to the thing just mentione’.

7. He needed so much else besides.