I added some colorful commentary. This should be pretty close to what you're looking for.

Copyfunction display-path {
  <#
    .SYNOPSIS
    quick shortcut to get env:PATH

    .DESCRIPTION
    Call Get-ChildItem with the the -path set to "env:Path" which actually just outputs out the child items of the current folder...

    .EXAMPLE
    display-path | Format-List


    Name  : Path
    Value : C:\Program Files\Eclipse Adoptium\jdk-17.0.2.8-hotspot\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPow
          erShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\PuTTY\;C:\ProgramData\chocolatey\bin;C:\Program Files\Go\bin;C:\Program 
          Files\dotnet\;C:\Program Files\Eclipse Adoptium\jdk-17.0.2.8-hotspot\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\Syste
          m32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\PuTTY\;C:\ProgramData\chocolatey\bin;C:\Program 
          Files\Go\bin;C:\Program Files\dotnet\;C:\Python310\Scripts;C:\Users\jedurham\AppData\Local\Programs\Microsoft VS Code\bin

    .NOTES
    not sure why anyone needs this

#>

  Get-ChildItem -Path Env:Path 
}



function folder {
  <#
    .SYNOPSIS
    shortcut to move between folder someone uses often

    .DESCRIPTION
    shortcut to move between folder someone uses often. 
    can be used to quickly navigate to common directories.

    .PARAMETER Username
    Moves to the C:\Users\currentuser\ Folder.

    .PARAMETER Scripts
    Moves to a hard coded path called 'C:\Users\currentuser\Desktop\Scripts'

    .PARAMETER Desktop
    Moves to a hard coded path called 'C:\Users\currentuser\Desktop\'

    .PARAMETER Help
    Displays this file.

    .PARAMETER root
    Moves to the root of the current drive. 


    .EXAMPLE
    folder -Username
    C:> folder -U
    You chose the -U  flag!! Moving to C:\Users\currentuser\

    .EXAMPLE
    folder -Scripts

    C:> folder -S
    You chose the -S  flag!! Moving to C:\Users\currentuser\Desktop\Scripts

    .EXAMPLE
    folder -Desktop

    C:> folder -D
    You chose the -D flag!! Moving to C:\Users\currentuser\Desktop\
    

    .EXAMPLE
    folder -root
    C:\> folder -r
    You chose the -R flag!! Moving to C:\

    .NOTES
    Needs a lot of work .... 

    v0.01

#>



  [CmdletBinding(DefaultParameterSetName = 'Default')]
  param(
    [Alias('u')]
    [Parameter(ParameterSetName = 'User')]
    [switch]$Username
    ,
    [Alias('s')]
    [Parameter(ParameterSetName = 'Scripts')]
    [switch]$Scripts
    ,
    [Parameter(ParameterSetName = 'Desktop')]
    [Alias('d')]
    [switch]$Desktop
    ,
    [Alias('h')]
    [Parameter(ParameterSetName = 'help')]
    [switch]$Help
    ,
    [Alias('r')]
    [Parameter(ParameterSetName = 'root')]
    [switch]$root
  )



  $switchoutput = 'You chose the{0} flag!! Moving to {1}{2}'


  if ($Username) {

    ## you need more comments in your code
    ## are you just trying to move the \user\current logged in?
    ## just use $env:USERPROFILE

    $targetFolder = $env:USERPROFILE
    $u = ' -U'
    Write-Output -InputObject ($switchoutput -f $U, $targetFolder, '')


  }
  elseif ($Scripts) {

    ## a little tougher here because you need to hard code this path
    ## we could also ask for it ask an addendum to this switch :P
    ## ill do it this way

    $targetFolder = $env:USERPROFILE
    $s = ' -S '
    ## it might be better to define this else 

    $scriptspath = 'Desktop\Scripts'
    $targetFolder = $env:USERPROFILE + $scriptspath

    Write-Output -InputObject ($switchoutput -f $S, $targetFolder, '')

  }


  elseif ($Desktop) {

    ## same as above
    ## it might be better to define this else

    $desktop = '\Desktop\'
    $targetFolder = $env:USERPROFILE + $desktop
    $d = ' -D '

    Write-Output -InputObject ($switchoutput -f $d, $targetFolder, '')


  }
  elseif ($root) {

    ## same as other but we can use $env:homedrive for the root of C:

    $targetFolder = $env:HOMEDRIVE + '\'
    $r = ' -R '

    Write-Output -InputObject ($switchoutput -f $r, $targetFolder, '')
  }


  else {
    Write-Output -InputObject "
        -H         Display help. This is the same as not typing any options.
        -U         Change to the 'Username' directory
        -S         Change to the 'scripts' directory
        -D         Change to the 'desktop' directory"
        -R         Change to the Root of home directory"

  }

  if (Test-Path -Path $targetFolder) {
    Set-Location -LiteralPath $targetFolder -Verbose
  }
  else {
    Write-Output -InputObject ('{0} was not found :( exiting' -f $targetFolder)
  }
}