What is an example of a sense group?

I know a sense group is a group of words that make sense when put together, often introducing a fresh idea. However, I’m not sure what an example of one would be. Is a verse in a poem one sense group or multiple? Here is an example that I am thinking about:

• ‘I’m the ghoul beneath the bed’   ( The Usual suspect by David Harsent )

Is ‘beneath the bed’ an example of a sense group?

And here is another one:

• ‘ The crane at last managed to reach’ (The wolf and the crane by Marmaduke Park)

Is this entire verse a sense group itself, or is it more than one?

I think what I am struggling with mainly is how to identify sense groups in phrases/ sentences. Is there a way to easily find them?