Fastai not getting installed on the system

Hey guys!
I am a novice to fastai
I have tried too much to use fastai in my pc and I face error after error relating to modules. Then I decided to use Colab server and follow the steps of https://course.fast.ai/start_colab.html. However, I again faced an error: No module named ‘fastai.structured’. I am really disappointed about using fastai. I can see that structured.py exists in …/old/fastai. I don’t know why I see that error. I would be happy if someone could help me!