While there’s no one right way to learn CW, there are many, many wrong ways, especially if your goal is to copy in your head.

The trick is to build a mental association between the rhythm of each Morse character and its corresponding letter.

fyi, nearly everyone that succeeds in achieving morse proficiency recommend strongly against any sort of visual cues like this. It’s an auditory “language” and adding visual interpretation steps just adds cognitive load and hurts in the long run. It may be fine if your goal is to learn max 5 words per minute or something extremely slow.

Like others said, such methods will not help achieve proficiency in morse. One needs to learn and associate sound patterns rather than dits and dahs