The first stage of digesting food is obviously when it first enters your mouth. Chewing breaks down food particles and mixes them with saliva which makes it easier to swallow.
Next, the food is swallowed. It then enters the oesophagus where it is pushed down by muscular contractions called peristalsis. When the food reaches the end of the oesopagus it releases into the upper portion of the stomach.
Now that the food is in the stomach, the gastric juices (that the stomach produces) get mixes with the food. This further breaks down the food particles, making them a substance know as chyme.
A muscular valve in the bottom of the stomach then releases the chyme into the small intestine, known as the duodenum. This is where lots of the digesting happends.
The villi are part of the lining in the small intestine. They play an important role in absorbing the breakdown products of digestion, and absorbing nutrients that are then transported to the liver.
From here, peristaltic movements push the undigested substance down the large intestine and allows it to mix with the bacteria. The bacteria can ferment some of the undigested material, producing short-chain fatty acids.
And then..Undigested and compacted material enters the rectum for temporary storage before exiting through the anus.