If you want to copy or remove a section of your song, you will need to know how to select multiple regions and how to split them. This is how to do it:
You start by selecting all the regions in your project by pressing Ctrl/Cmd+A, or by clicking in an empty space and dragging a selection that catches all of the regions. Next, you place the playhead where the section you wish to copy or remove starts. Press Ctrl/Cmd+E to split the regions (1). Now you want to split the regions at the end of the section as well, so you repeat the procedure with the playhead placed in the end position (2) (Ctrl/Cmd+A and Ctrl/Cmd+E will come in handy again!). With the section successfully separated, click in an empty space below the section and drag upwards to make a selection (3). Now you can either Alt+"click-and-drag" (4) or copy and paste it (Ctrl/Cmd+C and Ctrl/Cmd+V) to a new location, or press Delete or Backspace to delete it!
(1) Playhead positioned at start of section, regions split by pressing Ctrl/Cmd+E
(2) Playhead positioned at end of section, all regions selected again by pressing Ctrl/Cmd+A
(3) Section selected by clicking below the regions and dragging upwards
(4) Section copied by pressing down the Alt key and clicking and dragging to new location