Our school is close to a police station like 5 seconds away so I would call the cops with my phone and then they would blow the guy to hell

Drink the Doritos so I don't die a filthy casual

Well I've been wanting to be a a war general for quite some time sooooooooo lets get it on. First off my school has many small-medium sized rooms plus large open areas such as the theatre and the cafeteria. I would rally the strong people (Jocks, Archers, Karate people) and place around 8-12 in each room (over 2,000 people go to my school) in each room I will place a heavy thing/table to barricade the door and place 2 people on each side of the door frame. We would make weapons out of pencils, chair legs, sports equipment, kitchen knives, things students may bring, etc and make armor out of thicker clothing and books or sports equipment. In each room I would line up 3 tables in the far corner of the room 2-5 people would sit behind these tables and throw whatever they got at the attackers. at this time the 2 people behind the door frame jump out and stab or hit the attackers with knives and bats. Everyone else in the room is gonna have to perform a risky act, the remaining people will pick up chairs and charge at the attackers, the chairs may block some bullets but it is still a suicide strategy. However if these people can reach the attackers they will most likely trample/badly injure them as a chair leg to the face will most likely break a tooth, put out an eye, break a nose, or even shatter a part of the skull (my school's chairs are metal) now that I've got my small room strategy lets move on to the big rooms (cafeteria and theatre) in the cafeteria many students will hide behind the food stand and flip over tables for cover. Students should be armed with knives and kitchen utensils. Once the attackers rush in our Chair expeditionary force will charge and the students behind the tables will slowly push their tables forward putting more pressure on the attackers. The people in the back will throw knives and plates at the enemy. Now to the theatre, I have to admit this one is tricky but do able. Students will have to be armed with things like bats and knives as there are no usable weapons in the theatre *sigh. All students will hide behind chairs and stay very quite. The students will let the attackers get close then ambush from all angles including my theatre's low hanging balcony. This is pretty dangerous and death count may be pretty high. Yet it's the only plausable strategy as staying back will get many more killed. However if done right this will quickly overrun the enemy. Women and very young kids will stay in the school bathrooms and library, these rooms will be heavily blockaded with basically everything in the room and more. Now we have one last thing I like to call the Student Expeditionary Force. These guys are our last hope. They will be armed with metal bats and archery bows, plus they will be covered in football and baseball gear. Their job is to charge through the building and try to skillfully overrun any enemy groups they see using brute force and careful aim. These guys have the toughest and most dangerous job. Only the jockiest of the jocks and the toughest of the tough can be in this group. I will be barricaded into the principal's office radioing commands to the generals I have placed in each room. P.S. there is no hope if you're in the gym.

You'll need to describe the attackers more

Run, find a way to the vents, hide while the school gets destroyed

Good thing I took four years of martial arts. Stay in the class room. Go with the normal procedures. But I will stay closest to the door. Make sure I have a sharpened pencil. Then when he enters I impale his eye. Take his weapon(gun,knife,sword,coke bottle) and cripple his limbs with it. Making sure arrest is easy. Than I tape his mouth. We wait till cops come. If another guy walks in then I will have a better weapon. Rinse and repeat until safety arrives.