To do file merge, user need to use "Append Mode" or "Right Append Mode" together with "Batch Mode" during the operation.
Merge files Vertically:

1. Click "Replace" dialog
2. Change the Write Mode to ">>" before the Output File entry.
3. Click "Batch..." button and load the input files into the list.(see Batch Mode Operation for detail)

4. Change "Set Output File Name" to a fixed output filename, the Output File column will all be changed to this file name.
5. Click "Replace" in the select file dialog.
Merge files Horizontally:
The same as "Merge files Vertically" except that in step 2, user should select Write Mode ">>>" instead of ">>". see Write Mode(Overwrite,Append,Column Append) section for detail.
An easier way to make File Merge since Version 2.0:
User can select "Tools->Batch Runner" directly, after choosing files from directory, user can click "File Merge" button and finish operation, please refer to Batch Runner for detail.