The 501 under IRS code gives your non-profit sort of the non-profit status taxes wise. If you raise money for your office group and for the cause you want to serve, or for the services you provide, 501 (c) (3) gives you the tax exempt status.
I will get an attorney just beacause it's too much work to set it up, and it ain't easy to get the tax exempt status.
Also, it's not a bad idea to get an attorney , again pro bono, if you are small, because sometimes you might need advices in certain situations you might run into. At least, this is what I will do.