...
Maven greatly reduces the overhead of managing dependencies for a project. At build time, it automatically retrieves the most recent versions (or other version that you specify) of the libraries and jars on which your project depends, and – - perhaps more importantly – - the appropriate versions the libraries and jars on which those depend. Maven can be configured to retrieve files from a central location so copies of updated jars do not need to be distributed to individual developers.
...
*Use the default Maven project structure for new projects. Although there is nothing inherently superior in this structure, experience has shown that it's easy to sink a lot of time on debating and deciding on a project structure with the ultimate selection not being significantly better than the alternative. The default Maven project structure works, so save time and consider the decision made. Plus, you won't have to configure Maven to use a different structure.
http://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html
documents the default Maven project structure.
Resources
The official Maven project site
http://maven.apache.org
...