Go into the VBA project for the workbook, and under Microsoft Excel Objects, select ThisWorkbook. In here, select Workbook from the drop-down box at the top (which currently says "general"). This will create a Workbook_Open() procedure. Enter your code in here.
VB: AutoLinked keywords will cause extra spaces before keywords. Extra spacing is NOT transferred when copy/pasting, but IS if the keyword uses "quotes".
MYForm.Show 'Where "MYForm" is the name of your form.End Sub