When you begin Lollipop Chainsaw, after a short cutscene introducing Juliet and her boyfriend Nick and establishing that it is Juliet's birthday, you will find yourself facing a hoard of zombies outside of Juliet's high school. This section will teach you basic quick-time event and combat controls. The first task that you will have to perform when you gain control of Juliet is to saw through the gate in front of the school's lot. Hit either the Triangle or Y button depending on which console you're using, and tilt the left stick all the way down until the onscreen meter has depleted to chop through the metal gate. Once the gate is opened, you'll be faced with a crowd of zombies and a few exploding buses.
Use the Square or X button to hit the zombies with your pom-poms, and the Triangle or Y button to swing the titular chainsaw. The pom-pom attacks are much faster than the standard chainsaw attack, but also don't serve to do any real damage. Instead, repeated hits from the pom-poms will stun enemies, allowing you to pull off easy kills with the chainsaw. If you manage to get a group of stunned zombies clustered together, you can decapitate them all with one swing, which will reward you with tons of currency. Keep this in mind as you swing away at the zombies, but don't feel compelled to execute on all of these strategies just yet. This is the first battle, after all.
All of the zombies in this area will be of the base variety and won't be hard to kill at all. You should be able to cut them down with relative ease; with these dumber and weaker varieties, feel free to simply mash away with the chainsaw, as you don't particularly need to stun them before killing them and you don't have much in the way of combos unlocked as of yet. Once the initial group of enemies is dead, proceed down the linear path into the parking lot. Run past the exploding car and the dead student. You will soon come upon a stranded student trying desperately to fend off the zombies from atop his car. You will come upon situations like this several times per level, where you will find yourself faced with stranded civilians in need of help. If you manage to defeat the zombies in the area and protect the civilian while doing so, you will obtain a nice coin bonus. If, however, you don't manage to defend the civilian while the zombies attack him/her, the fallen survivor will come back as a particularly strong zombie and attack you. With that in mind, definitely try to save this civilian and all others you see.
Saving this guy won't be hard. The zombies will drag him off of his car, but when you approach they will turn their attentions to you. You will have to kill six zombies in order to save the civilian. Again, these aren't the toughest of zombies so use a mixture of pom-pom attacks and chainsaw swings to kill them. Once the civilian is saved, approach him to receive your reward and watch him be carried off by a rescue helicopter. Just after saving the civilian, though, you will be accosted by a zombie school bus driver and his terrible driving skills. A flying car will send Juliet backflipping through the parking lot as the bus crashes ahead.
Approach the bus' broken door and climb inside by hitting either the Circle or the B button, and then run down the length of the bus to collect a lollipop. Lollipops in Lollipop Chainsaw serve as a way to restore your health. By hitting any direction on the D-Pad, you can pause the action and pop a lollipop, which will instantly heal you. You can carry up to five at a time on the default difficulty level, but harder difficulties will force you to juggle fewer lollipops. Snag the sweet and proceed to the back of the bus, where you will have to cut your way out just like you did with the gate.
When you jump out of the other end of the bus, you will be met with a nice pile of coin. Collect them all and proceed ahead through the parking lot. By hacking at the soda machines and trash cans against the wall to the left of the crashed bus, you can break them and extract more coins. It's a good rule of thumb to always saw things that look breakable, like soda machines, trash and recycling bins, and potted trees, as they will often spew out extra coins that you will be able to use in the in-game shop later. When you are done chopping up the scenery, head down the alley to the left just in time to see another bus crashing ahead of you.
As you approach the crashed bus, two legless zombies will crawl out from beneath a partially-opened shutter. There will be five of these crawling enemies for you to dispense of in all. The best way to deal with the crawling zombies is to use the attacks mapped to the X or A button. These low swipes will chop up enemies on the ground. Combo these attacks together to make short work of the five enemies who will crawl out from under the shutter. These low enemies can sometimes be a bit tricky to hit, so if it looks like you're going to miss with an attack or be hit by one of their crawling strikes, hit the Circle or B button to dodge over them and hit the low attack button in mid-air to deal a powerful downward strike to the ground.
Once the crawling zombies have been taken care of, an arrow will appear over the hood of the bus. Approach it and hit the onscreen button to go vaulting over the bus and into the next area of the level.