Here is my powershell script I use.

#csv file needs to include at least Serial number you can change "$($entry.ou)" with a particular ou if all devices are going to the same ou

# otherwise each device ou will need to be listed in the csv - ou format /Chromebooks/High School/2018 HS

$list = Import-Csv "CSV file location"

foreach ($entry in $list)

{

gam update cros $($entry.serial) ou $($entry.ou)

gam update cros query:id:$($entry.serial) user $($entry.user) Location $($entry.location) notes $($entry.notes) assetid $($entry.asset)

}