Procedure

1. In main menu, select File → Merge TMX Files....
   The following dialog appears:

   
2. Enter the name of the file that will contain all merged data in the Merged TMX File text box or click the Browse... button to select a file from the file system.
3. Use the Add Files button to select the files to be merged from the file system.
   The dialog shows added files:

   
4. If you want to remove files from the list, click the corresponding Remove File buttons () on the leftmost column.
5. Click the Merge TMX Files button.