6/8 is a common compound meter: six eighth notes per bar. Many jigs and folk tunes are counted as two groups of three (one-and-a, two-and-a), so the felt pulse is 2, not 6. That is a counting habit, not a second accent engine in this app.
This page presets 90 BPM, 6/8, traditional drum. The engine accents only beat 1 of the bar (beat index 0); the other five beats are weak clicks. It does not add a second automatic accent on beat 4. If a tutor wants that extra accent, you supply it — the metronome will not.
Open the app to change BPM or mode. Learn the six clicks first, then count them in the grouping your tune uses.
The app pre-sets to 90 BPM, 6/8, traditional mode. To adjust, use the controls inside the app after it loads.