How to instantiate Main Window Form Correctly?

How to instantiate Main Window Form Correctly?

I'm trying to make instance of the Main Form1 but I don't know clearly
where/how to do it.
in Main Program entry point there is Application.Run(new
ProgramTalking()); do I replace it with Form1 MyMainForm = new Form1();
MyMainForm.Show(); ?
I'm kinda lost in how to correctly instantiate and where to do it. For
example I can instantiate my second Form2 and store it in memory but first
Form1 just runs and I cant have any access to it from Form2 despite
setting fields and properties to public. However I can effortlessly access
Form2 from my From1. Thank you for any help.