Not sure how much time you have, but if you do not have much I strongly recommend "Learn PowerShell In A Month Of Lunches" [1]
Basically means that if you can spend about one hour every day on the text and exercises in the book you will be able to grasp PowerShell scripting in about a month.
[1] https://www.manning.com/books/learn-windows-powershell-in-a-...