Normalizing a table in Access is one of the most important steps toward having a database that actually works like a database. Typically, when you are the user of a database, you should be able to type information in one place and it should be accessible everywhere else. Normalization is the process of making sure that fields are placed in the correct tables, according to the primary key(s) of the table.
In Access, there is a tool to help with this process, which is called the Analyze Table wizard. You can also use it to confirm what has been built already. This wizard will look at a table, and give suggestions for separating the existing fields into more than one table. The nice thing about this wizard is that you can ignore suggestions, or improve upon them, name the new table suggestions (if you decide to go with the suggestions), and call out the primary keys. It is an especially helpful tool if you are struggling with the normalization process.
Check out this video that shows you how to use the Analyze Table wizard: