extract specific string from the field returned

Class CustomAdInfo {
    $UserName
    $Group
    $Email
    $Manager
}

[char] 'y'..[char] 'z' | ForEach-Object {
    $getADUserSplat = @{
        Filter         = "Name -like '$_*'"
        Properties     = 'SamAccountName', 'memberOf', 'EmailAddress', 'Manager'
        ResultPageSize = 256
        SearchBase     = 'CN=Users,DC=ab,DC=cd'
    }
    foreach ($user in Get-ADUser @getADUserSplat) {
        foreach ($group in $user.MemberOf | Get-ADGroup) {
            [CustomAdInfo]@{
                UserName = $user.SamAccountName
                Group    = $group.Name # <= You need to choose an attribute here
                Email    = $user.EmailAddress
                Manager  = $user.Manager
            }
        }
    }
} | Export-Csv 'C:\Users\Downloads\Members_and_Groups.csv'

Above code returns Field Manager value as CN=manager-id,CN=Users,DC=ab,DC=cd in csv. Manager field is bound by CN user type and Domain details. Expectation is to replace these, extract only manager-id from the string and assign it to class property Manager. Am a beginner, couldn't find anything helpful on the internet. Anyone could help me here?

Add a constructor to your class definition where you can extract the common name from the manager's distinguished name. Details on the regex pattern used in the class .ctor can be found here: https://regex101.com/r/tAx4jM/1.

class CustomAdInfo {
    $UserName
    $Group
    $Email
    $Manager

    CustomAdInfo($user, $group) {
        $this.UserName = $user.SamAccountName
        $this.Group = $group.Name
        $this.Email = $user.EmailAddress
        $this.Manager = $user.Manager -replace '^CN=|(?<!\\),.+'
    }
}

[char[]] ([char] 'a'..[char] 'z') | ForEach-Object {
    $getADUserSplat = @{
        Filter         = "Name -like '$_*'"
        Properties     = 'SamAccountName', 'memberOf', 'EmailAddress', 'Manager'
        ResultPageSize = 256
        SearchBase     = 'CN=Users,DC=ab,DC=cd'
    }
    foreach ($user in Get-ADUser @getADUserSplat) {
        foreach ($group in $user.MemberOf | Get-ADGroup) {
            [CustomAdInfo]::new($user, $group)
        }
    }
} | Export-Csv 'C:\Users\Downloads\Members_and_Groups.csv'