Hear each letter as a rhythm, not as bits. People who count "two dots and a dash" hit a wall around 10 WPM. The mnemonic under each target lands big syllables on dahs, small ones on dits. K is KAN-ga-ROO. Hum it.
Learn. Tap and hold the key, or hold space. Short press is a dot, long is a dash. Pause submits. The tree is a lookup, not a training crutch.
Listen. Plays a letter, a group of five, or a real word from your unlocked alphabet. Type what you heard.
Tune. Drill the dot-vs-dash threshold itself. The gap narrows as you nail it.
Chart. Full reference. Tap any letter to play.
Koch method. Start with K and M. Each new letter unlocks at 85% over 12 reps, or 6 in a row. Default speed is 18 WPM characters at 8 WPM spacing (the ARRL standard). Fifteen minutes a day will beat one big session a week.