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. Select the Open Generated TMX File checkbox if you want the merged file to open automatically in the editor once merging completes.
6. Click the Merge TMX Files button.