To restore a lun just select it in the Backup Archive and Restore GUI and proceed with the restore. If you are overwriting an existing LUN you will have to offline the original LUN before performing the restore. The only requirements that I am aware of are that the LUN must be restored to the root of a volume or qtree. For example: the restore path can be /vol/vol1 or /vol/vol1/qtree1, replace volume/qtree names as appropriate.