All ballads are 4 beats to the bar. Traditionally, ballads are written in simple time (4 - 4). Where a little more rhythmic interest is required, they can be transcribed to compound time (12 - 8).
For beginners, translating from compound time to simple time is easier to understand than translating from simple to compound time. So we start with this exercise.
Ask yourself the following questions.
How do we translate the first beat of the second measure? A compound beat translates to a triplet or hemiola in simple time.
A minim is two beats of (4 - 4) time. A dotted minim makes two beats of (12 - 8) time. So in translating from simple to compound time put a dot after the simple time rhythm.
What about compound rhythms in simple time? In simple time we write a compound beat as a triplet with 3 over the beam. This translates to an ordinary beat (no 3 above the beam) in compound time.
If you have a strong feel of 2 in your compound time signature, then use duplets in preference to multiple dotted notes. Duplets are simple time beats in compound time.
To halve the beat in compound time write two quavers with the number 2 above the beam. This is a duplet. It says play 2 in the time of 3. (Recall how a triplet says play three in the time of two).
Four over a beam is shorthand for two duplets, meaning 4 in the time of 6.
In common time there are 4 crotchet beats to the bar. In cut common time there are four crotchets, two beats to the bar.
Beat for beat, a crotchet in common time translates to a minim in cut common time. One bar of common time translates to two bars of cut common time.