When you have created your level 3, do the tutorial and use a Bond on it to add members. Once you have done this, the character is ready to begin collecting Warbands. Warbands is run once every 7 hours, every single day, at the very same time each day. You can find the time that it begins using the ticker on the Runescape Wiki. There is also more information there on how Warbands works:
http://runescape.wikia.com/wiki/Wilderness_Warbands
Basically, you go out to the level 12 Wilderness north of edge where the camp spawns. Hop worlds until you find one with an active camp. Wait until other players have cleared the camps, then loot the supplies. Run down to the bank after looting and join the Friends Chat (FC): "Safe Trades"
In the FC, find a trustworthy buyer, since you will need to trust trade the supplies. They can be transferred by the other party PKing you, or by you dying to an NPC in the Wild, if your combat levels differ greatly.
You can collect 25 supplies 3 times per day on each character. 25 Supplies = 2 Million Gold. So each character can make 6M gold per day. A bond costs ~6.1M and lasts 14 days, therefore this method can break-even after one day. However, some players do not have time to do all 3 runs per day. Even with 1 run per day, however, you will make 2 x 14 = 28M per 14 days. After factoring in the price of a bond, that is 28-6 = 22M profit per 14 days, per character.
This all takes about 10 minutes per run, per character once you are experienced and have a good rhythm going. That means you can earn ~12M per day if you do 2 runs per day on 3 characters, which works out to 360M each month, with only 1 hour of work per day.
This is the BEST moneymaking method in Runescape right now. If you are serious about earning gold quickly in-game, you should learn how to use this method.
Of course, if you don't want to do this all day, or this isn't earning you enough money, you can always buy RS3 Gold (click here) or RS2007 Gold (click here) from our site. We are in-stock and delivering billions daily! We also can buy your RS2007 / RS3 Gold from you at competitive rates.
Good luck at the Warbands!