Audacity
Audacity is a free and open-source
digital audio editor
and recording application software,
zoom in Ctrl + 1 on the keyboard
zoom normal Ctrl + 2
zoom out Ctrl + 3
open an audio file
To keep a selection:
use the Selection Tool to highlight the audio
that you want to keep.
To ensure that you like this selection
you can listen to the selection by pressing the SpaceBar
or click the play button.
Click Edit, Remove Special then Trim Audio or
Ctrl + T
only the highlighted part of song or content will remain.
to move the recording to the beginning.
use the Time Shift Tool button.
Click on the icon
or use F5.
With the Time Shift Tool engaged,
use the left mouse to drag the recording to the required time.
A yellow line will appear when snapped to the very beginning.
To cut:
highlight the unwanted audio with the Selection Tool
by clicking the left cursor on your mouse,
and drag to the required length.
click on Edit, Remove Special and Split Delete
or press Ctrl + Alt + K.
The highlighted audio will now be removed.