With the appeal of the earworms songs we hope that it is not a question of “having to” but rather a question of “wanting to”. But seriously: the memory is like a muscle, it needs to be trained and exercised. The ideal is listening relatively intensively at the beginning (the learning phase), thereafter listening periodically to review what you have learnt and refresh your memory.
In practical terms this means listening to the whole album the first day, in order to ‘tune your ear in' to the sounds of the target language. Then listen regularly, several times, over a period of one or two weeks, making sure that you listen to every track equally as many times.
After this, go through the booklet and test your knowledge, picking out any gaps that you may wish to concentrate on.
Lastly, the review phase. As we all know, memories fade, so it is important to refresh your memory by using the course at your leisure, say, once a week for the following few weeks. Thereafter, monthly. This review phase is crucial as it consolidates your knowledge and transfers it into your long-term memory. Although this demands self-discipline, it is of course without effort, as you are only listening to music. The result is that you will be able to recall the words and phrases with the same ease that you remember your telephone number!