Account for held notes without inventing attacks
The dotted half in the 3/4 melody combines a half note's two quarter beats with one more quarter beat. Count its duration as three beats beginning at the attack. At the next bar boundary its duration would be complete. You do not attack it again when you say 2 or 3. The count marks elapsed beat positions; it does not command a fresh press whenever a number is spoken.
A useful dry test uses the score without the instrument. Say the right-hand pitches of bar 1 on the three numbers. For bar 2, say D on 1 and continue counting 2 and 3 without saying D again. Meanwhile, tap a separate surface once on every number to represent the left hand. The spoken note and the tapping now have different attack patterns, but both remain inside the same three-beat bar. This preserves the coordination problem while removing key finding.
When you return to the instrument, keep the right D held as the left changes from G2 to B2 to D3. If both hands release after beat 1, the upper note has lost two beats. If the right repeats D on each bass note, its duration has changed into three quarters. Both errors can sound organized because the hands act together, but neither matches the notation. Watch the upper note's duration while reading the lower attacks rather than using hand simultaneity as your definition of correctness.
Manual Next note follows the next attack in either hand. In this second bar, a step can advance the bass while the held right D remains highlighted. That is a visual reminder of simultaneous time, not a request for the right hand to repeat. The synthesized reference includes a small release gap, so judge the written duration from the note value rather than trying to reproduce every detail of the electronic envelope. The browser does not assess whether your finger held D or whether a pedal prolonged it. No pedal is needed for this exercise.
Find the two groups inside six eighth notes
The 6/8 melody begins C4, D4, E4, G4, E4, D4, all eighth notes. Read the first three as the subdivisions of one main beat and the last three as the subdivisions of the next. Say 1-and-a for C, D, E, then 2-and-a for G, E, D. The fingers are 1, 2, 3, 5, 3, 2. The leap from E4 to G4 begins the second group; it does not add an extra subdivision between the two groups.
The left hand makes that grouping explicit. C3 begins with the first right-hand C and lasts a dotted quarter. G3 begins with the right-hand G and also lasts a dotted quarter. Each bass note spans three melody eighths. The left hand therefore changes on the numbered syllables, not on every spoken syllable. Read the beams in the upper part alongside those lower dotted quarters. Together they show the same division into two groups.
In bar 2, the right changes to dotted quarters too. C4 occupies the first group, and G4 occupies the second. The left plays C3 then G3 at the same attacks. The subdivision has not disappeared merely because fewer notes sound. Continue to feel three equal smaller units within each held note. If you lengthen the first bass note because the right has stopped moving, the second group arrives late and the bar becomes uneven.
Count the first bar on one repeated key before restoring its pitches. Keep the bass as two taps, one on each number. This isolates the difference between six melody attacks and two bass attacks. Then restore C, D, E under the first bass note and G, E, D under the second. If the second group starts before you have said the final a of the first, you have compressed a subdivision. If you pause after that a, you have inserted time between groups that the score does not contain. Neither problem requires changing the melody's fingering to investigate it.
Check the join between the two 6/8 bars as well. The last right-hand D4 belongs to the final a of beat 2. The next C4 begins on the following 1, together with the bass C3. Do not hold D for a whole main beat just because it is the final note in the group. Its eighth-note value matches the other five melody notes in that bar. Conversely, do not cut the first C4 of bar 2 into an eighth. Its dot belongs to a quarter note and asks it to fill the entire three-part first beat.