I am an experienced PHP programmer using Django for the first time, and I think it is incredible!
I have a project that has a lot of apps, so I wanted to group them
Your top-level urls.py (also named in your settings.py) must be able to use a simple "import" statement to get your applications.
Does import project.apps.app1.urls work? If not, then your PYTHONPATH isn't set up properly, or you didn't install your project in Python's site-packages directory.
I suggest using the PYTHONPATH environment variable, instead of installing into site-packages. Django applications (to me, anyway) seem easier to manage when outside site-packages.
We do the following:
Django projects go in /opt/project/.
PYTHONPATH includes /opt/project.
Our settings.py uses apps.this and apps.that (note that the project part of the name is part of the PYTHONPATH, not part of the import.