I've been trying to teach myself #PowerShell for defensive purposes and need to organize my resources, so here's a list:

1) A 5-step tutorial covering storage, output, input, loops and decisions. Great for getting started.
https://powershell.org/2022/07/learn-powershell-in-5-painless-steps-storage-variables-arrays-hashtables-step-1/

2) An array of options to get exposure to #PowerShell
https://jdhitsolutions.com/blog/essential-powershell-resources/

3) Of course probably the most obvious source, Microsoft. Their "PowerShell 101" introduction and "Sample Scripts" to see real examples like working with registry entries.
https://learn.microsoft.com/en-us/powershell/scripting/learn/ps101/00-introduction?view=powershell-7.2

4) Although it isn't a guide to learn #PowerShell, it serves as a good step after. You'll learn about obfuscation techniques, why #RegEx is great but painful, and there's even a tool at the end!
https://unit42.paloaltonetworks.com/tag/powershell-scripts/

5) PowerShell by Example. A great initial learning resource but also a reference when a simple syntax escapes the mind.
https://powershellbyexample.dev/