How to get my DSLR camera to focus?

My step dad gave me his old dslr camera as he just got a new one. It's a Nikon D3200. It takes great pictures of flowers, but if I'm trying to get it to focus on a face it focuses on something else. I'm new to these cameras so is there a particular setting I should put it on, or what should I do?

Manual and focus peaking

There's a small turntable on the right side of the flash close to the power button. For starters, I suggest getting familiar with the normal shots first (lightning icon) and the normal with flash shots (green icon). But for better quality, try turning to the letter icons.

In the manual, which you can easily find as a PDF in a Google Search, you will discover an option that allows you to choose one of the 11 different autofocus points on the screen. You want to focus on the eyes and not be closer than the lens can handle. In auto mode the camera tries to work out what kind of photo is being taken and can often get it wrong if other elements of the scene are prominent.
Manual here: See p40

You can do it with spot exposure too.

Most people who shoot with DSLRs a lot will turn all of the focusing points off, and just have the one center AF point. This allows the user to focus much more precisely on the exact point and then recompose the shot.

One important setting that you'll want to change if it hasn't been already, is the way the AF system is activated. By default, the D3200 is set up to where the shutter button activates the AF system. However, there's an option to turn the AF off at the shutter button and on at the rear AF button. Doing so will provide much more control over when and where the camera focuses. For nearly all DSLR users, this is among the first changes made to the default settings.

The times where you're likely to want to use multiple-AF is with wildlife or sports where you often don't have time to focus and recompose.

Your camera has the ability to set different focus points. You need to read the Users Manual to learn how to use them.

Read the manual. You'll need to play around with your focusing and metering settings.

You're too close.

All of your answers are in the manual.

Wouldn't hurt to reset all settings and learn how the AF system works (which involves reading the manual). Most likely the system is picking an AF target you're not expecting.

Make sure you are a comfortable distance away from your subject. Lenses have a minimum focusing distance, inside of which the lens can't focus. If you need to photograph a close subject, you either need a macro-capable lens, or close focusing filters (basically screw-on magnifying lenses).

The camera may also fail to focus if your scene is too dark (e.g. Indoors at night) or doesn't have good contrast.

Nikon, try and find the focus point. Instead of using all of the auto-focus point. Set it to a single focus point. Set it in the middle and when you're about to shoot, compose your shot while holding the shutter halfway to stay in the same focused area.