How do I play (and sing) a chord pattern song?

Question

There are many questions I have regarding a chord progression so decided to use a simple song to start... Happy Birthday, since we all know it.

C                 G             
Happy birthday to you
                  C
Happy birthday to you
                       G  F
Happy birthday to dear name
F     C        G  C
Happy birthday to you

I don't understand, from looking at this progression, how I am supposed to know the timing (3/4 or 4/4?), the measure breaks, when to change chords, or even the timing when singing, and probably many more details I'm not aware of.
To start with a simple example... Starting with the first line, I envision I could strum like either of the following:

(D)   (D)  (D) (D)  
Happy Birthday to ...

or

(D)   (D)      (D)
Happy Birthday to ...

It seems to depend a lot on how fast you sing, etc.

Am I overthinking this or is this sort of thing just imprecise in the first place and up to the individual to make it sound like something?

I will clarify this question with any comments I receive so thanks for any assistance!

Answer 1

...from looking at this progression, how I am supposed to know the timing (3/4 or 4/4?), the measure breaks, when to change chords, or even the timing when singing...

You don't!

The chords merely constitutes a guide for those who already know the song, i.e. the melody, the meter ("timing") and style. From a perspective of conveying a song to someone who doesn't know it, and has no chance of hearing an example of it, it is an inferior notation. But for the live musician who knows the song but might not remember all the chords it can be just what he or she needs.

The guidance you get is that the chords generally are placed above the word or, preferably, the syllable that is sung on the beat where the chord is "in action". How you play it - strumming all beats, or just the first beat in every bar; as a march, or with a latin feel... - is all up to you. If you want to play it like some "original" performance, you'll have to listen to that and figure it out for yourself, or find some other source of notation or guidance.
(Sometimes there is an indication of the style to perform it in, such as 'waltz', 'raggae', or 'ballad', but you'll still need to know and choose a suitable way of playing that style for the particular song.)

So,

...is this sort of thing just imprecise in the first place and up to the individual to make it sound like something?

Yes.

Answer 2

For that song, as an example, you could pretty much pop the strums in where you want.

It can be logical to strum every syllable, or every accented syllable, or every measure - the important pieces for this song are the chord changes. If you are a beginner you can focus on only downstrokes, or if you are a little more adventurous you can use up and down, or you can even arpeggiate it - as long as you don't clash too much with the melody.

You could try playing it in various styles - you can even get away with it as a waltz (just tried it now for fun - although it does sound weird)