When using Natural for Linux and Cloud as a development server, you should use the editors which are provided by NaturalONE to edit the Natural sources on the Natural server.
To edit DDMs you use the DDM Editor. For maps you use the Map Editor. For all other Natural object types you use the Natural source editor.
To use your test projects on the Linux server in NaturalONE:
In the Natural Server View, map to the Linux server.
Select the library.
In the context menu select Add to new Project to download the library into a new Natural project of the workspace.