I seem to create a main.py file when I try to create new project

HI,

Im working my way through teaching myself Python as  beginner .

I seem to create a new main.py when I try to start to writ ea new program.

This cant be right.

Also, when I write a litrle bit of code and run it, it keeps running some code I thought I had closed and  finished with!

Can anyone point me in the right direction.