The basic principles are the same between phones and dedicated cameras. So any beginners photography guide that covers things like the exposure triangle and scene composition will help. You can find tons of info for free online, so no need to go to school for it. And being digital with live preview and immediate reviewing, just put it in manual mode and play with setting adjustments to see how they affect the image.
A quick and dirty version:
Shutter speed: faster = freeze motion, but needs more ambient light. Slower = better for low light, but can have motion blur.
ISO: Lower = better image quality (aka reduced noise), but requires more ambient light or slower shutter to compensate. Higher = makes the sensor more sensitive to light for better low light photos with a faster shutter speed, but increases noise that can hurt the overall image quality (and phone sensors are very prone to ISO related image noise).
Aperture: larger = better low light photos, but a shallow depth of field (how much is in focus). Smaller = larger depth of field (helpful with fast action or scenes where you want more in focus), but needs more light, longer shutter speeds, and/or higher ISO settings. This is usually a fixed setting on the phone that can't be changed. It's represented as f/#. So an f/1.8 aperture would be larger than an f/2.0.
If there's a specific scene or subject you are trying to shoot, feel free to ask and we can give more specific advice.