I believe you have to edit your pom.xml to include another library.
<dependency>
<groupId>your own custom group id</groupId>
<artifactId>your own custom artifact id</artifactId>
<version>some version number</version>
</dependency>
For example, if you wanna add ControlsFX Library to your project: https://github.com/controlsfx/controlsfx/wiki/ControlsFX-Features
you could do:
<dependency>
<groupId>org.controlsfx</groupId>
<artifactId>controlsfx</artifactId>
<version>11.1.1</version>
</dependency>
Hope this helps!