You basically start off the game on an island where you learn how to play. I.E How to fish, start a fire, kill, chop trees, mine, smith, walk, run etc.
Then it takes you to Lumbridge where you are level 3 in combat i.e. you can kill a rat and spiders. You can either travel to Varrock and get money out of the bank and start the mining/smithing thing or go get some meat and chop down wood to put your cooking up or start fishing in Draynor or do some quests. I'd say at first to get a quest done. Possibly Farmer Fred's. Turn left out of the Castle gates and keep going until you come to a field of wheat then turn left and go into house and talk to the NPC. This allows you to get some more money when you do the quest. After doing this quest then you can either go kill some chickens or some cows. Either way sell the feathers or cowhides. It really is a good game especially when you start getting your mining up but can be annoying when more experienced player's steal you Coal Rock :(