Andor Stitcher
Fusion includes built-in image stitching / tiling / montage functionality.
See also Montage and Specimen Navigation for details on how to acquire a montage image.

The stitcher settings in the image processing tab.
To start the Stitching Process press the stitch button

Note: The stitch button will display the progress of the stitching process. This process can be stopped by pressing the stop button beside it.
Stitching Options
Align in Z

The Align in Z option will align features along the Z Dimension as well as in the X and Y dimensions.
Note: Default is off. Recommended to be used with Focus Map acquisitions when focus of the sample varies in the Z dimension.
Channel for Correlation Matching

The final section under the stitching options is Channel for Correlation Matching. This is the channel in the protocol that will be used to find features for aligning captures. In the case of User-Defined the user will have to select which channel to use. In the case of Auto, the first channel in the protocol is used.
Furthermore Stitching can also be enabled during acquisition in the Protocol Manager tab:

When Apply Stitching is enabled, the options set in the Stitching section of the Image Processing tab will be applied
Troubleshooting
If the resulting image does not look correct (for example, the overlap or the rotation of some / all images is incorrect, please check the F.A.Q (Frequently Asked Questions).
A video guide can be seen here: Image Processing Options- Deconvolution and Stitching