Guitar Beginner Question (Beware, pretty weird questions)

playing to music helps.
for example: "Rockn Roll Ruby" of "Rockabilly Riot"
The key is A..means the chords are: A-D-E
Starts in A...(we don`t talk about *7 Chords or something like that, only to find the rhythm)
Try to play it and try to find the rhythm.

And, best way is to find a teacher if you want to learn playing.
It helps for the first time.

Greets
Brett