Create Backups using snapshots and symlinks

Backup.ps1

Function snapshot() {
    param(
        [String]$Path,
        [String]$Access,
        [String]$BackupName
    )
    Write-Debug "Backing up $Path to $BackupName..."
    #Create VSS Snapshot
    $shadowCopy = (Get-WmiObject -List Win32_ShadowCopy).Create([System.IO.Directory]::GetDirectoryRoot($Path).ToString(), $Access)
    Write-Verbose "Querying Win32_ShadowCopy for element with ID $($shadowCopy.ShadowID)"
    $shadowCopyWmi = Get-WmiObject Win32_ShadowCopy | ? { $_.ID -eq $shadowCopy.ShadowID }
    #Build valid path for link creation
    $snapshotPath = $shadowCopyWmi.DeviceObject + "\" + $Path.Replace([System.IO.Directory]::GetDirectoryRoot($Path).ToString(), "")
    #Build vallid target path
    $targetPath = ("D:\BACKUP\") + $BackupName
    Write-Verbose "Symlink target: $targetPath"
    Write-Verbose "Snapshot location: $snapshotPath"
    #Create Link
    cmd /c mklink /d $targetPath "$snapshotPath"
}

Function New-Backup {
    <#
.DESCRIPTION
Creates a VSS-based backup of a given folder.
The backup will be symlinked to D:\BACKUP\%DateTime_FolderName%

.PARAMETER path
Specifies the path to backup. The snapshot will be created for it's root direcory.
The symlink will point to the given path.

.EXAMPLE
Create-Backup -Path D:\myFiles\databases
#>

    param(
        [Parameter(Mandatory = $false)]
        [string] $Path = (Get-Item -Path ".\").FullName
    )

    if (Test-Path $Path) {
        Write-Verbose "Creating Snapshot for given path..."
        [String]$target = [datetime]::Now.ToString("dd.MM.yy_HH-mm") + "_" + [System.IO.Path]::GetFileNameWithoutExtension($Path)
        Write-Debug "Target: $target"
        snapshot -Path $Path -Access "ClientAccessible" -BackupName $target
    }
    else {
        [System.Management.Automation.ItemNotFoundException]::new("The Path specified for backup couldn't be found.")
    }
}

New-Alias -Name Create-Backup -Verbose New-Backup

Hi,
I am newbie on powershell, how do I feed parameters into this powershell script ?
I have tried .\script.ps1 from a powershell command line but it only replies with:
VERBOSE: Performing the operation "New Alias" on target "Name: Create-Backup Value: New-Backup".
I would like to modify it so that I am able to run this in task scheduler with a target path and a destination path.
thanks
Gavin