When you come back:
Tuning. There are tuner apps for Android, and I assume for iPhone too. Guitar Tuna is the Android app I fall back on if I haven't got a hardware tuner to hand.
Chords. Start with the ones using open strings. E, A, D, C, G, Em, Am, Dm. "House of the Rising Sun" used to be a traditional song to start a guitar career on (there is an F in there too). Once you get reasonably comfortable with them as you'll find them in the chord books, experiment a bit with barres across two or three strings - for example, barre the top three strings at the 2nd fret with your forefinger and use your middle finger on the 3rd fret of the B string for D.
Barres. Once you've got comfortable with the chord shapes using open strings, you can move them up the fretboard with your forefinger taking the place of the nut. So if you use your forefinger to fret across all 6 strings at the first fret and use the other three fingers to make an E shape, you're playing F. The same applies to the A shape and C shape, and the Am and Em shapes.