Stat > DOE > Response Surface > Define Custom Response Surface Design
Use Define Custom Response Surface Design to create a design from data you already have in the worksheet. For example, you may have a design that you created using Minitab session commands, entered directly into the Data window, imported from a data file, or created with earlier releases of Minitab. You can also use Define Custom Response Surface Design to redefine a design that you created with Create Response Surface Design and then modified directly in the worksheet.
Define Custom Response Surface Design allows you to specify which columns contain your factors and other design characteristics. After you define your design, you can use Modify Design, Display Design, and Analyze Response Surface Design.
Continuous Factors: Enter the columns that contain the continuous factors in the design.
Categorical Factors: Enter the columns that contain the categorical factors in the design.