Memory functions through three steps:

Acquisition. Before you can remember something, you first must learn the information. This is called acquisition. This acquired information is then put into temporary nerve-cell pathways in the brain. These pathways are where you store short-term memory.

Consolidation. In order for something to be placed in long-term memory, the nerve pathways have to be strengthened and reinforced. This process, called consolidation, can take weeks or even months. There are several factors that affect whether or not information will be put into long-term memory. For example, you are more likely to retain information if it relates to pre-existing memories or somehow stimulates you emotionally. Also, it doesn't hurt to have a good night's sleep, as this too helps you retain information.

Retrieval. When people retrieve information, they are literally "recalling" it from the nerve pathways. The brain reactivates a particular pathway, and information is remembered. This process can be fast or slow, depending on how familiar you are with the information and how well you learned it in the first place.