How to create custom app and module. I have using this via Oracle VM virtualmachine

I am using ERPnext via oracle VM machine. I have no idea where i have to create custom app and module since it was only accessible to ubuntu. no file access.
Need help how to find directory and run some python customizable scripts

First of all, go to your “frappe-bench” folder.
Usually, it is located in “~/frappe-bench”
And to make changes on the python scripts, go to “~/frappe-bench/apps” folder.
It will show you all the frappe framework app that stored in your machine.
And find .py to make changes

To create an app:
inside the frappe-bench folder, type this command in your command line:

bench new-app {your-app-name}

for further explanation:
Create an App (frappeframework.com)