Saving Data

It is possible to store data in the Personal Macro Workbook.
You might want to make the Personal.xlsb file visible if you need to store data on its worksheets.
You can hide the workbook easily afterwards.

Adding worksheets to your Personal.xlsb

This workbook is normally hidden however you can unhide it by pressing (Window> UnHide) and selecting "Personal.xls" from the dialog box ??
If you have a Personal.xls created it is open every time Excel is open meaning your macros are always available. You can only see the workbook from the VB Editor as it is always hidden.

If you want to add a custom button to you standard toolbar then you should put the code to be executed when the button is pressed in a module in your Personal.xls.