1. Go to the page of a download by clicking on the 'available for download here' page of the ClustalW2. 2. Download clustalw-2.*-macosx.dmg. '*' is the minor version number. 3. A disk image is mounted when you double-click the clustalw-2.*-macosx.dmg. 4. Open the disk image and copy clustalw-2.*-macosx folder in a hard disk. 5. Select [File]→[Parallel Editor]. 6. Click the [Import Sequence] button and read sequence files. 7. Click the [ClustalW] button. 8. Set a path of ClustalW in 'Select ClustalW' of the ClustalW Parameter dialog. 9. If you want to use the ClustalW2 , select the 'clustalw2'.