It appears the only way to FULLY edit an Astrolab preset is via AnalogLab. You can edit some basic functions via Astrolab Connect (even though it’s focus seems to be getting you to purchase new sounds).
You can also do limited preset editing on the Astrolab itself but changing a multi preset part key range and transposition, if possible, seem difficult since no visual feedback is available to show you what you just did.
It doesn’t explain anything in detail. It’s just an outline of what the tool does, which doesn’t help once you realize what editing a preset, with visual feedback, requires.