One more note on Part 1- Pre-recording:  For completeness, I'll point out the Dub feature and DUBMODE parameters to flesh out & fine-tune the initial recording.  DECAY has been set to 0 here (no amount of 'loop aging').  Dub & DECAY will be essential if you want your sampled 'grains' to fade out when adjusting the PLY-START position.

Part 2 – 'Granular' Playback

After pre-recording, adjust the PLY-LENGTH parameter to the 'grain size' that you want.

Here is a very rough idea of some range areas (highly dependent on recorded material).

These initial settings assume that SPEED is at 1X or 100 (-1X or -100).

0.005 – 0.040 Secs  =  A fairly steady resonant tone.

0.040 – 0.150 Secs  =  Rapid, individual repetitions begin to emerge.

0.150 – 0.250 Secs  =  Multiple notes and glides start to become apparent.

0.250 – 0.500 Secs  =  Very short phrase and note cluster territory.

0.500 – 2.000 Secs  =  Short motifs develop.

2.000 – 12.000 Sec  =  We certainly left 'granular' far behind at this point.

In Playback / Dub mode, it's now possible to make adjustments to RESOLUTION and PLAYSPEED.  Pitch changes & sample 'grain' length, reverse, pause / stall … plenty of adjustments to make here that will fine-tune the sample snippets (in real time, if desired).

Now, it's a matter of using the expression pedal to shift around the PLY-START position.  Keep in mind that the Looper is continuously … looping (playing back or dubbing).  So, 'jumping' to a distant PLY-START position will mean that the Looper needs to 'catch up' to that point.

In other words, some playback samples will be longer than the current PLY-LENGTH, which will be the difference between the 'old' PLY-START point and the 'new' PLY-START point.  One shot through to reach the new setting, then the current PLY-START and PLY-LENGTH settings take effect.