1st we are going to talk about fingert postion.
Your 2nd finger(middlefin.)should be on the A string
your 1st finger(poiting fin)should be on the G string
and last your 3rd finger(ringfin) should go on the D string

this makes it much easier to play these 3 string chords

we will start with C Major the notes are G C D played together makes 
C Ma

G:|—8——|
D:|—9——|
A:|—9——|
E:|————|

now we go to F A C notes played together makes F major

G:|—6——|
D:|—7——|
A:|—7——|
E:|————|

now we are to D G B these notes make up the G major chord

G:|—4——|
D:|—5——|
A:|—5——|
E:|————|

now we come to the C F A this is the F Major chord

G:|—2——|
D:|—3——|
A:|—3——|
E:|————|

These are the major chords and all you have to do is bring the G 
string finger(indexfin) down one and then you got yourself 
a minor chord..for exsample

G:|—1——|
D:|—3——|
A:|—3——|
E:|————|

here is your song
G:|———————————————————|
D:|———————————————————|
A:|—5~~~——78p7———7—5——|
E:|—————————————8—————|  use anywere on the neck
plus

Intro (Play once)
G|———————————|————————————|——————————|————————————|
D|5—78—7——75—|5—78—7——75——|——————————|————————————|
A|——————8————|——————8—————|3—56—5——53|3—56—5——53——|
E|———————————|————————————|——————6———|——————6—————|