Morse code - how to start?

As a corona project I was thinking about learning the Morse alphabet and I found this shared deck Morse Code Sound and Lights - AnkiWeb but I need some advice for how to start.

Included with the deck are sound files at 30 WPM but that is completely impossible for me. Fortunately there are separate sound files with other speeds, both lower and higher, available as separate downloads.

Should I start with the slowest sound files to learn to distinguish between long and short as well as character and word boundaries and make “fast” progress, or is it better to start with a higher WPM and make slower progress?