Instructions
Order all of your probes to start collecting supplies and create more probes to increase your gather speed.
Start creating offensive units at your stargates, gateways and robotic facilities. Continue creating units as long as you have the supplies to do so. Units with long-range attack capability will be especially effective as the zerg will send a combination of both air and ground forces.
Divide your forces into three equal groups and place them at the three entrances to your base. Each group must have some long-range attack capabilities to combat the mutalisks and other airborne attackers.
Send a probe to each of the ledges surrounding the entrances to your base and have them build additional photon cannons to augment your anti-air defense. Keep those probes there after they have finished to repair damaged cannons. Cannons can also be placed to block the entrances and create choke-points for your armies to hold.
Keep a standing force in the center of your base to repel the nydus worms that will burrow past your defenses and deposit units in the heart of your base. Void rays are a good unit for this as they cannot be hit by ground units and can quickly destroy a nydus worm and its allies before too much damage is sustained.
As new Protoss heroes arrive to assist you in the battle, start creating the more powerful units they bring with them like Void rays and Carriers.
Continue to augment your defenses until the counter shows you have slain more than 1,500 zerg units. At this point, the attacks will dramatically intensify until your base is completely destroyed. Hold out for as long as you can but do not be discouraged when you eventually lose.