After the end of the beginning FMV, when you can move Cloud, check the body of the closest guard twice to get two Potions. Head north towards the door where the other AVALANCHE members go. Defeat the guards who attack you and then go through the door to your left to go outside. Meet the AVALANCHE members, Biggs, Wedge and Jessie, learn a bit more about Cloud, and then name him and Barret. Head up, right, up and left through the door. You will come to a T-junction; follow the other members to enter the plant itself.
Talk to Barret, and he joins you in your party, so you can now fight with him. Talk to Biggs to open the first door, then to Jessie to open the second one. Go through the passageway to the south after the second door to get a Phoenix Down in the chest. Talk to Jessie to enter the elevator. Once inside push the button with the up/down button with two arrows on. Listen to Barret and Cloud argue then follow Jessie out of the elevator and down the red stairs, and through the door. Jump over the gap; talk to Jessie and down the ladder. Get the Potion half-hidden in the smoke, and down the stairs and ladder. Go south to the next area. Follow the pipes, down the stairs to the Save Point. Follow the walkway south. Pick up the Restore material (which you can’t use yet). Watch as Cloud gets freaky and then plants the bomb, and your first boss battle of FF7 begins………….
Don’t worry about it’s Search Scope attack as it doesn’t cause any HP damage. Make Cloud use his Bolt magic and Barret attack with his gun. Use this method and Limit Breaks to inflict damage until it’s tail goes up. Ignore what Cloud says and don’t attack while it’s tail is up or it will counter big time. Just heal if needed or defend until the tail goes down and continue like before.
Equip the Assault Gun you receive for Barret after defeating the boss. You now have ten minutes to escape the plant. Retrace your steps, save if you like, up the ladder, over the pipes and talk to Jessie near where the Potion was before. Free her and retrack to the elevator. Go up a level and talk to the AVALANCHE members to open the doors back to the T-junction where the game takes over. Watch as the reactor explodes.