Start with these exercises. Once you got the basic groove and strum emphasis, it would be easier for you to start learning to strum beginner's songs listed below.
lessons 1-6: beginner's guide
Focus first on learning to follow basic rhythms using simple open-string chords.
LESSON # 1: Bass note strumming
In this lesson you will learn:
Guitar tuning
The note names of the standard open strings (E, A, D, G, B, E)
Reading a chord diagram
Basic major chords progression (A, D, E)
Playing a bass-note strumming
Song: 'Leaving on a Jet plane' by John Denver
lesson #2: down-up strumming introduction
In this lesson you will learn:
The use of plectrum and fingernails for strumming
Down-Down strumming pattern
Down-Up strumming pattern
lesson #3: beat emphasis rhythm downstroke
In this lesson you will learn:
Chords G, D7, and C
Proper positioning of your fingers when playing chords
Overcoming the C chord
Beat emphasis rhythm using downstroke
Song: 'Happy Birthday to You'
lesson #4: down up rhythmic strumming + mute technique
In this lesson you will learn:
Chord Progression G, C, G, D
The use of alternative G and C chord, commonly use in folk and pop music
Down and up rhythmic strumming with muting technique