There is a function in Sound Organizer called Divide. This feature allows you to cut/divide a track through the waveform displaying mode.
To do this, select an item in the My Library directory, then select the file you want to edit. Click again on Edit Mode and then Divide. The waveform displaying mode should activate itself. Click the PlayBack image button in the control area in order to play the file, then click the Add Divide point on the position you want to start the editing. Drag the mark left or right to select the portion you want to cut. Click Start and then Start Divide.
For additional help, I would recommend checking the support page created specifically for this operation: https://us.en.kb.sony.com/app/answers/detail/a_id/36946/~/how-to-cut-or-divide-music-files-in-the-sound-organizer-software