Click the ✎ button in a sampler track's header (or open the Sample tab) to open the Sample Editor. You'll see the sample's waveform with two trim handles.

• Drag the handles to trim the playback region in / out.
• Reset trim — restore start = 0, end = 1.
• ▶ Forward / ◀ Reverse — flip playback direction.
• ⏱ Preserve / ⇔ Varispeed — toggle granular time-stretch (next section).