Home Sharing Contracts

My friend and her boyfriend are moving in with the boyfriends mother. The mother does not own the property - it is rented via the council. Seeing as I am a legal student my friend asked me to draw up a rough copy of a ‘flat sharing contract’ basically just stating that they all agree to pay a certain amount for various bills, etc

However, my conveyancing and property law is a little rusty and I dont feel I could do a good enough job at present. I have searched online for copies that I can change to suit the situation of my friend but cannot find anything that wont cost me money! Im a poor student!
Any help would be greatly appreciated.
Thanks x