Things You'll Need
Instructions
Basic Door Automation (Non-Adjacent)
Place your doors in their intended positions. They cannot be next to each other because the power connection will have to terminate at each door.
Place a lever near the doors.
Place a line of redstone dust running from the lever to each door. Make sure that each door is at the end of its own branch of the line. They should now all open or close whenever the level is thrown.
Adjacent Door Automation
Place two or more doors on blocks next to each other.
Place a redstone repeater next to each door, ensuring that each one is facing the door.
Place your lever nearby.
Place a line of redstone dust between the level and your redstone repeaters. The rear of every repeater must be in contact with the dust to form a circuit. All of your adjacent doors should now respond to the lever being pulled.