Choose timing before complexity
The left hand can make an accompaniment feel grounded with very few notes. Start by playing the root at each chord change and letting it sustain for the appropriate duration. Count the beats between changes aloud. If a chord lasts two measures, resist adding movement just because the hand feels idle. A clearly placed bass note establishes the harmony more effectively than a busy pattern whose attacks drift away from the pulse or arrive late when the right hand changes shape.
Find a register that stays clear
Try the bass note in two nearby octaves and listen with the right-hand chord. The lower option may add weight, while the higher one may keep a quiet arrangement clearer. Avoid clustering several close notes deep in the bass before you understand how they interact. Add an octave only if the span is comfortable and the extra weight suits the music. You do not need to stretch beyond a relaxed reach; alternating notes or using one note can provide an equally valid arrangement.
Add movement with a harmonic reason
Once the roots are steady, try a fifth between two main bass attacks or a short approach to the next root. Listen to the melody and confirm that the added note fits the intended harmony. A detected slash chord in AudioChords may suggest a specific bass note, but verify whether it is sustained or merely passing in the recording. Practice the bass alone through the section, then reunite the hands. Keep a simpler version ready for singing practice. The left hand's first responsibility is reliable support; decorative motion should make the phrase clearer rather than distract you from its direction.