If you are planning on using CBC/HB 5 for you analysis then you can probably import your design and data directly into CBC/HB using the new .csv import feature. You can find details on the layout of your design and response files in the CBC/HB 5 manual.
If you want to generate a .cho file using SSI Web then you can import your design into the software and then import your data using the accumulate paper and pencil data option available in the analysis menu.