Diference about Beside and Besides

Compare and use.. do not confuse: 'Beside'-'Besides'

BESIDE, without "S", is used to mean NEAR or NEXT TO. While BESIDES, with the "S" means IN ADDITION.

Besides, with "s", might seem to suit as a linker between two sentences separated by a period; quite as 'IN ADDITION', 'ADDITIONALLY', 'FURTHERMORE' or 'MOREOVER' usually does to commence after a period. Within a one single sentence, you still can move, at ease, to carry out the sense of an increase of a notion, with several other terms such as ALSO, TOO, AS WELL AS and FURTHER

PS. 'DECIDE' is entirely something different.