Sorry for the late reply 
I don’t know about you but when I program, I like to run my code on the terminal of the operating system I’m using windows or Linux and not on the IDE (this is just my preference)
So it’s kinda similar to colab.
Colab uses Linux as it’s operating system and the a python version is installed in it by default with some Machine learning modules and others.
Normally in any operating system u are using, if u want to run a code from the terminal all u simply need to do is open the terminal and type the command cd 'code dir' to navigate to the code directory and then python code.py to run it. This is no different with colab.
Once u upload ur code on colab whether from Google drive or from local directory, it is stored in the current working directory EG;
Assuming u uploaded a folder named ‘project’ and this folder has ur code named ‘project_class.py’, all u need to do is to type !cd project to navigate into ‘project’ folder and then u type !python project_class.py to run the code on colab.
If u want to edit the code, simple go to the left panel and click on particular file u wish to edit and a text editor will appear on the right side.
Hope this helps