Your question seems to be referring to the way in which Hemingway uses imagery in this excellent allegorical novel. Imagery is a term given to the way in which an author paints an image of what he is describing by appealing to as many of the five senses as possible: sight, taste, touch, smell and hearing. The more senses that are appealed to, the stronger a sense of the picture that the author is trying to paint.
There are a number of excellent examples of imagery in this deeply descriptive novel. Notice the following example of when Santiago guts a dolphin that he catches on his epic voyage:
He felt the maw heavy and slippery in his hands and he slit it open. There were two flying fish inside. They were fresh and hard and he laid them side by side and dropped the guts and gills over the stern. They sank, leaving a trail of phospherescence in the water. The dolphin was cold and leprous grey-white now in the starlight...
Notice how, in this quote, Hemingway combines the senses of touch and sight. He describes the feeling of the maw of the dolphin and the hardness of the two flying fish, and then the coldness of the dolphin's corpse, just as he describes how the corpse looks "leprous grey-white" in the light of the stars. Likewise, when he drops over the guts, we see the trail of phospherescence in the water. This is a good image because it combines two senses to helps us see the scene that Hemingway is painting. Hopefully this example will help you to find other examples in the book. Good luck!