'Woning' and Expats/Students

I noticed there are certain 'woningnet' sites available throughout different cities in the Netherlands.  I don't entirely understand how it operates, but it seems the housing is catered towards those with little (or no?) income.  I understand how the registration process etc works for the sites themselves, BUT, I'm trying to figure out if it's legal or not for me to respond to the offers posted, and what exactly I need to do?

I am a student in the Netherlands so I'm looking to get a place to share with a few people for next year as my current place is only for the first year.  I do have a BSN number, although I don't have a job (isn't worth it since I can only work 10 hours a week.....) and therefore no income.
I understand that in order to respond to an offer, I need to have an income statement provided by the government?  Is that correct, and if so how would I go about attaining it?
Finally, once I have all the documents etc, what if I want to get a place with multiple rooms to rent with a couple friends?  Is this possible as long as the entire household doesn't make above the income threshold?  Also how would rental payments work...would one of us pay the entire rent per month, and reimburse that person?  Or would it be split against everyone paying to the landlord?

If you can answer any of the questions, please tell.