Userform to specify number of rows/columns

I was hoping someone could help me with this part of my Evaluation template.

Attached is a copy of my Vendor Evaluation template. It automatically creates new worksheets identicle to the Master sheet with the Vendor's name.

These worksheets get scored on the MAIN worksheet.

What I'd like to do is have a userform that will allow the user the ability to specify the number of rows under each criteria in the MASTER worksheet. As I don't have much experience with userforms I was hoping someone could help me with this.

It would be desirable if the user could see a userform once the workbook opens asking if they would like to continue with the current workbook or create a new workbook. If creating a new workbook then a copy of the original MASTER and MAIN worksheet open and the current worksheets deleted.

If the user picks new workbook then it would ask them to specify the (3) criteria headers and the number of rows needed under each criteria.

If possible it would be nice to have them specify the number of evaluators and have the empty columns hidden based on the MASTER worksheet.

Thanks in advance !!