So... I'm extremely new

[trousersnack]

I recently just got my first keyboard with the intent to learn how to play, and eventually move up to a piano.  Having played other instruments, I'm familiar with music theory and reading music, but what I'm not 100% on is technique.  I know so far that (and correct me if I'm wrong)

*All your fingers are used
* left hand generally for chords, right hand for melody
*You use the side part of your thumb

However, I'm not sure how to finger chords.  I'm trying to learn Aura Lee, and Ive been fingering the C major with my thumb, middle finger, and pinky.  The D major, Ive been using my pinky, first finger, and thumb.

Can anyone tell me the correct technique?

[lostinidlewonder]

...The D major, Ive been using my pinky, first finger, and thumb.

The first finger is the thumb, or maybe you mean the first finger as the index? Thumb is 1, index is 2, middle finger is 3, ring finger is 4 and pinky is 5.

 If you are playing C major as CEG, then LH 531 is the best if you are not going to stretch for higher notes immediate after playing it (and you generally don't have to do this with easier music) if for instance you where to play (CEG) then soon after an A above the G you may change the fingers to LH 532 then hit the A with the 1. If we had to do a lower note like (CEG) then a B below the C, then we may use  (321) and then hit the B with the 5.  

If you are simply playing chords and then moving to the next chord, then use the fingering that distorts the shape of the hand the least amount.

In your case you are playing Cmajor: CEG as 531 and D maj (DF#A) as 521. The thing is that both chords can be played with the same shape of the hand. This is something that can be tricky to notice especially when there is a black note present, but the shape of your hand when you play the CEG, try to hold completely freeze and hold that shape. Then move your pinky to the D and the rest of the fingers should come above the correct position for the D major. This technique highlights that the same shape of the hand can produce the same chord family sound (in this case the major chord). If we are changing fingers around and have no reason to do so, then we are making things more difficult on ourselves.