Please read your manual. It's the little booklet that came with the camera in the box. Alternatively, you could download the pdf copy from Canon US website.
Your cameras has the "Green Box Mode" (Full Auto) where the camera will do all the work for you. In addition, you have the Scene Modes available (marked with these little icons on the knob). I don't think it poses a big problem to judge your situation and select the right one. A 'field trip' sounds as if the Landscape Mode could work well for most situations.
Read up about composition. Little efforts here can make a big difference for the pictures.