You are not allowed to play the Goblin Goon if you like to play "modern". Also the Goblin Sledder and the Goblin Vandale are not allowed.

The idea is easy: put as many goblins as fast as possible into the battlefield and attack and attack and attack.... but be careful not to sacrifice your goblins for nothing: try to bury creatures your opponent controlls with you or directly deal damage to the player. Don't hesitate to sacrifice a goblin for a goblin granade, 5 damage are always a good deal.