desktop icons are gone after update on my laptop

The icons should not disappear unless you managed to:

1. Login a different account. Use the Go emenu -> Home folder to verify that the home folder is the expected login. Make sure the Desktop folder in there has the files you desire.
2. If it is the expected user, you may have hidden the icons using the Finder menu -> Preferences -> General
3. If the files are gone from the expected desktop folder, command-shift-period (.) three keys held simultaneously can show hidden files, or files that have been made into hidden files. If they aren't even visible as hidden files, check your trash can to verify you didn't dump the files there.
4. If iCloud is syncing the files on your desktop according to Apple menu -> System Preferences -> iCloud and you haven't logged in the right iCloud account, that could cause the files to disappear. Check under Go menu -> Computer and open the boot hard drive icon to verify there isn't an iCloud storage folder at the root level of the hard drive. Sometimes files that were on the desktop get relocated there.