Script window for adding three new columns, two columns with constant fixed values, and one column with numbers

[#1]

Dear all 

I would like to create a script to add three new columns in my data table. Two columns will have fixed constant values and one will have numbers. Ideally script should open up a pop up window and ask for the constant values. Thankyou for helping me with this 

1st column heading: Process (Script should open a pop up window asking for the constant value in the process column)

2nd column heading: Lotslot (Script should open a pop up window asking for the constant value in the process column)

3rd column heading: Dose (this column with have fixed set of numbers starting from a fixed number on first row (to be input by me by a popup) and then decreasing through the column by a value of 2 till the end of column)

[#2]

Here is an example, taking the script example from the Scripting Index for New Window.  For the most part, it was just replicated 3 times with your specification changed for each entry

names default to here(1);
dt=current data table();
ex = New Window( "Process",
	<<Type( "Modal Dialog" ),
	<<Return Result,
	V List Box(
		Text Box( "Enter the constant for the Process column" ),
		H List Box( myEditBox = Number Edit Box(  ) ),
		H List Box( Button Box( "OK" ), Button Box( "Cancel" ) )
	)
);

//  the Modal window must be closed before the following code runs

If(
	ex["button"] == 1 // not canceled
, dt << New Column("Process", set each value(ex["myEditBox"])),
	Write( "CANCEL" ); // cancel button or red X was pressed
);


ex = New Window( "LotSlot",
	<<Type( "Modal Dialog" ),
	<<Return Result,
	V List Box(
		Text Box( "Enter the constant for the Lotslot column" ),
		H List Box( myEditBox = Number Edit Box( ) ),
		H List Box( Button Box( "OK" ), Button Box( "Cancel" ) )
	)
);

//  the Modal window must be closed before the following code runs

If(
	ex["button"] == 1 // not canceled
, dt << New Column("LotSlot", set each value(ex["myEditBox"])),
	Write( "CANCEL" ); // cancel button or red X was pressed
);


ex = New Window( "Dose",
	<<Type( "Modal Dialog" ),
	<<Return Result,
	V List Box(
		Text Box( "Enter the starting number for the Dose column" ),
		H List Box( myEditBox = Number Edit Box( ) ),
		H List Box( Button Box( "OK" ), Button Box( "Cancel" ) )
	)
);

//  the Modal window must be closed before the following code runs

If(
	ex["button"] == 1 // not canceled
, dt << New Column("Dose", set each value(ex["myEditBox"]-(Row()-1)*2)),
	Write( "CANCEL" ); // cancel button or red X was pressed
);