How to put an iphone on silent?

I'm getting an iphone next year, and I wanna take it with me to class because I don't really wanna put it in my locker. So anyways, how do I put it on silent/vibration mode?

On the left side of the phone, there's a small switch, and a two-way volume button. Flip the small switch on the top and it will be in silent (vibrate) mode.

You flip a little switch on the left side. When you see a red line, it means the phone is on vibrate.

The button on the left side

There's a silver bar on the left side of the phone and if you can slide it up and down if you want it on silent make sure the orange part of the bad is showing if not make sure it is all silver

There's a button above the volume control that allows you to do that.