Try This :-
in Form 1 Class create variable like this:-
public static string a;
then on Button Click event pass the value to variable declared like this. Suppose if I want to Pass TextBox Value then :-
a = TextBox1.Text
write this following code, this will pass your textbox value to variable a.
Then on Form 2, suppose You want to show the value of Form 1 in Label control then write following code:-
label1.Text = Form1.a;
you can see the value passed in textbox on Form 1.
Answer to Second Question.
In Solution Explorer there is a file named Program.cs. In that you will find the following method :-
static void Main()
In this method in Third Line i.e.
write the name of the form which you want to call first .
Any query still, plz reply or comment.