You need to have your focal point on something that has some contrast and is stationary. You will have a hard time focusing on, for instance, the sky, or a field of grass that is moving in the wind. The focal point also needs adequate lighting.
I've never used the guide mode, so have no help for you on that.
Make sure you have the complete users guide to your camera.... you can download it from the Nikon website. The one that came with my D3100 was very incomplete. Also search around for some books specific to the D3200, you might find them helpful.
working on it in Middle TN Nikon D3100
35 mm 1.8 Nikkor 18-55 mm Nikkor VR 55-200 mm Nikkor VR 55-300 mm Nikkor VR 150-500 mm Sigma OS Feisol CT3471 & Markins M20 ballhead