ATTENTION EVERYONE

my friend and i are trying to beome suppliers to a big JSE listed company.
we were asked to submit a business portfolio.
what exactly is it?
how long should it be- how many pages?
i understand there should be a cover letter- i a page enough for that?
what details should be provided/submitted?
how should it all be laid out.

were both nobodies who are trying to just get our foot in the door.
we need to make a good first impression but not overdo it.

all advice/assistance welcomed.

thanks