Hi and welcome to the club. This is something you will enjoy and hate at the same time.
There are a lot of youtube channels to teach PowerShell. Check this video
Also, you can read some online articles... But the main thing first is to see how you like to learn. Do you prefer listening, watching, or reading?
PowerShell is free, and the IDE (the interface you use to write a script) is also free such as VSCode or ISE.
One of the good ways to learn is to create a scenario. for example. If you need to automate AAD User creation for your organization, try it. Ask here or in other channels, we are all here to share, learn and help.
Learn About Graph API SDK, as you can control Microsoft 365 solutions using it.
The best way to learn is to read about the thing u want to do and then try, fail, try and succeed.
There is a nice book here that can teach you PowerShell for Sysadmin