Magnolia 5.6 reached end of life on June 25, 2020. This branch is no longer supported, see End-of-life policy.
Maven is a tool for managing project dependencies and building your Magnolia project. You must have Java installed in order to proceed. You need a Java Development Kit, a Java Runtime Environment (JRE) is not sufficient.
Please see Maven setup for the details about how to setup Maven to get access to Magnolia resources.
Further reading