You're reading the documentation for an older, but still supported, version of ROS 2. For information on the latest version, please have a look at Humble.
Building ROS 2 Package with eclipse 2021-06
You cannot create a ROS 2 package with eclipse, you need to create it with commandline tools. Follow the Creating your first ROS 2 package tutorial.
After you created your project, you can edit the source code and build it with eclipse.
We start eclipse and select a eclipse-workspace.
We create a C++ project
We see that we got C++ includes.
We now import our ROS 2 project. The code is still in the old place.
We see in the source code that the C++ includes got resolved but not the ROS 2 ones.
We now see that the ROS 2 includes got resolved too.
Adding Builder colcon, so that we can build with right-click on project and “Build project”.
With PYTHONPATH you can also build python projects.
Right-click on the project and select “Build Project”.