The Systems Reference Document (SRD) (v3. 5) (5e) contains the rules of D&D, which are important to consult as you learn to play. Read the Basic Rules and Spells sections. If you’re planning to be the Dungeon Master (DM), read the Monsters and Magic Items as well. Don’t worry about any of the other sections for now, they’re for advanced players. Be advised: The SRD is not comprehensive, and lacks vital information on subjects like character generation and gaining levels. Printable character sheets are available for fifth edition here.