No module named 'omni.isaac.core', after pip install isaacsim

Hi, I am new for Isaacsim. and I found I could use pip to install isaacsim yesterday, but when I would like to import Class from omni.isaac.core.(like: from omni.isaac.core.materials import OmniGlass) it said No module named ‘omni.isaac.core’, Did I miss something?Thanks for any help.

Have you done import isaacsim?
https://docs.omniverse.nvidia.com/isaacsim/latest/installation/install_python.html#running-in-interactive-interpreter-notebooks

Yes,

Then you’ll probably have to start the SimulationApp() before importing those packages.

Thanks, I just misunderstood before.

Can you successfully launch the app?
I’m getting this error right now… Pip installation still doesn't work?