Hello ClaMac23,
this is the barebones to import the CSV and set the information in AD to what's on the file:
$users = Import-Csv 'UserInfo.csv'
foreach ($user in $users) {
Set-ADUser -Identity $user.Samaccountname -Description $user.Description -Office $user.Office -Department $user.Department -Title $user.Title -Company $user.Company -manager $user.manager -employeeID $user.employeeID
}
Take care with the manager property, as it has to be in a specific format, just the display name won't work.
More information about the Set-ADUser cmdlet: