How do I merchant on runescape? ?

Ok so today I decided to start merchanting on runescape. I tried buying water runes for 12 gp each and selling for 13 gp each but it doesn't buy or sell. I looked at ge in game guide and bat bones are rising. I put in an order for 4k bat bones at market price. Only a few bought so far. I am planing to sell the bat bones once they reach 300 gp each. I am p2p. Will this method make me some cash? I also am wondering what are merchanting clans and how do I run one of my own?