Zoom Tool (magnifying glass) - Use left mouse to expand and right mouse to contract.   Notice the ruler at the top that shows the number of seconds.

Expand Vertically by grabbing the bottom border and dragging.

Use selection tool (I Bar) to and delete button to remove unwanted segments.

Amplify or lower sound by selecting the segment and use the Effect tool Amplofy.  Use Edit ... Silence to mute a segment.

Import audio by using Project ... Import Audio.  You can also drag and drop music onto the track.

Timeshift Tool (double arrow line) enables you to move a segment to another location on the timeline.

Effects to consider:  Fade In and Fade Out

Tracks can be lowered in volume or muted using the controls at the left of the track.

Saving Project and exporting as MP3. (File ... Save As or Export as MP3).  ID3 Tags are used by audio players to identify your file  by title, artist, album (Use your podcast name), track number, year and genre (podcast must be changed in iTunes).  Comments can provide information about the content of the podcast.