To rotate a knob, you have different options of interaction described here.
By enabling lockable buttons, some buttons (such as any effect's HOLD button and the Sampler's MUTE button) can be locked in a particular state (pushed or released) by touching them and dragging away your finger.
This option prevents your device from going to sleep automatically while running Ricepad.
When you quit Ricepad, the default behavior is to autosave and close the session, so that when you run it again it will be loaded back and will start from the beginnning. This option minimizes the use of the memory when Ricepad is not running.
Alternatively you can decide to keep on running the session on the background in order to play along with other apps. Note that this option works only on devices where multi-tasking is supported.
Recording kills output
When sampling with this module you can decide if the audio output must be muted. By enabling this option you can avoid feedback problems.