The Lost Mine of Phandelver is an adventure for four to five 1st Level characters (though it can be played with fewer people.) You can find everything you need to play this in the Starter Set, including the adventure book, the Starter Rulebook and five premade character sheets as a sample guide. During the adventure, your characters should advance to Level 5. The adventure is set a short distance from the city of Neverwinter in the Sword Coast region of the Forgotten Realms setting. You can find a copy to read The Lost Mine of Phandelver's Rule Book for free here.
More than 500 years ago, clans of dwarves and gnomes made an agreement called the Phandelver's Pact, by which they would share a rich mine in a wondrous cavern called as Wave Echo Cave. In addition to its mineral wealth, the mine contained great magical power. Human spellcasters allied themselves with the dwarves and gnomes to channel and bind that energy into a great forge (The Forge of Spells) where magic items could be crafted. Times were good, and the nearby town of Phandalin (pronounced fan-duh-lin) prospered as well.