How to use MultiSpec to Combine Satellite Image Bands into an RGB Image

I am not an experienced user of this program, but after reading the manual an experimenting, i found the following which seems to work:

1. Load the image which contains the first band, e.g. "z17_nn10.tif"
2. Press "OK" to any dialogs which appear
3. Command "File: Open Image"
4. In the Open dialog:
   • select the second file, e.g. "z17_nn20.tif"
   • click the "Link to active image window" checkbox
   • click "Open"
   • select the third file, e.g. "z17_nn30.tif"
   • click "Open"
   • click "Cancel"
5. All three bands are now loaded, but not yet drawn as merged.
   Command "Processor: Display Image"
6. In the Channels section put "1 2 3" or "3 2 1" depending on how you want the bands interpreted.
7. Press OK, and OK again for the histogram computation
8. You should now be looking at a full-color image.
   Select the area you're interested in by dragging a box with the mouse.
9. Command "File: Save Image Selection to GeoTIFF"
   Give your output file a name, and you're done.