You can find the User Manual for Vista with Essentials L2 on the HunterLab website here:
https://www.hunterlab.com/en/products/benchtop-spectrophotometers/vista/

You may also access it directly using this link:
https://mirror-develop-hunterlab.s3.amazonaws.com/media/documents/Users_Manual_for_Vista_Essentials2_A60-1021-530.pdf