How to crate a Auto Open Choice button & need go to sheet1 and sheet2 based there choice

I have crated one spreadsheet for a net calculator
Sheet1 has FIXED account calculation and Sheet2 has VARIABLE account calculation
I need crate an Auto Open choice button for my net calculator
Calculator should be pop-up such as;
When open, then if I select FIXED should be go to sheet1
If I select VARIABLE should be go to Sheet2

Pls help

I mean OptionButton1

anyone help plsss