You can learn your first song in under an hour if it’s one with only a couple of simple chords.  You'll need to practise to play it well, though!  There are literally hundreds, probably thousands of songs that you can play with three chords.  Just search the internet.  At this early stage, it would really pay to use a teacher to help, but you can do it using the internet or a book.

1.    Find a song that you’d like to learn
If you’re going to learn it in under an hour, you’ll need to already ‘know’ the song.  I’m guessing that you do, otherwise why would you want to learn it?  I would look for songs, which use one of the following three groups of chords:

1.    Chords A, D, E  (Key of A)
2.    Chords D, G, A  (Key of D)
3,    Chords G, C, D  (Key of G)

If you have a teacher, they will help you find a song and get you started.  If not, it needs to be in the right key or group of chords.  For example, if you want to learn 'Twist and Shout', by the Beatles, the chords are D, G, A, so you will need to find a lesson which uses these chords, otherwise if you try to play along to the original recording it won’t sound right.

On the internet, you really can find the tab and or a lesson to most songs you’ve ever heard of.  If you’re starting out, on Justin Guitar, there are well over a hundred video lessons for beginners’ songs:

2.    Learn to fret the chords
So, in 'Twist and Shout', the chords are D, G and A.  If you are completely new to this, it’s going to be very difficult to get your fingers to fret the chord.  Expect this frustration – we all go through it.  Look at the chart, which comes with the lesson and put your fingers on the first chord, D.  It will feel very strange and perhaps uncomfortable.  Remove your hand and reapply the chord.  Do this a few times before moving to the second chord.  A note here:  teachers have different ways of fretting chords

3.    Working out the chords to songs
This is an advanced skill, but one which will be well worth developing.  As soon as you are able, you should try do this before looking ‘for the answer’.  It will develop your ear.