Clarification of scheduled task creation with PowerShell 4.0...

Hi all,

I'm new to scripting so please forgive any poor terminology, etc...

I've written two scripts which work perfectly when run manually.  The first creates a backup, the second deletes the same backup.

At the end of the first script I want to add the creation of a task which will trigger the second script to run ten days later.

<# Scheduled Task Creation #>
$A = New-ScheduledTaskAction -Execute C:\Users\myUser\Desktop\PowerShell\snapshotDestroyer.ps1 -Argument $snapName $listFilePath
$T = New-ScheduledTaskTrigger -At <# 10 days later? #> -Once
$P = New-ScheduledTaskPrincipal -UserId "myDomain\myUser"
$D = New-ScheduledTask -Action $A -Principal $P -Trigger $T
Register-ScheduledTask destroyTask -InputObject $D

The task appears to get created & start running, but it doesn't do anything...

So my questions are:

What is the correct syntax for the arguments of New-ScheduledTaskAction

AND

How can I trigger after 10 days? I see a weekly & monthly option, but nothing in between.

Thanks in advance.