Looking at the documentation at

https://www.jenkins.io/doc/book/pipeline/

It's impossible to know:

• How to run a shell script.
• How to copy files and folders around. Possibly using wildcards in shell scripts.
• How to delete a directory.

Trying to find out how to do these simple things resulted in a waste of time. Google didn't help either.

You may probably want to add some simple examples explaining how to do simple tasks (copying files, creating zip files, etc.), what "Jenkins plugins" are, which are the most frequently used ones.

Documentation says:

sh is a Pipeline step (provided by the Pipeline: Nodes and Processes plugin) that executes the given shell command.

But then following the link to the "Pipeline: Nodes and Processes"

https://plugins.jenkins.io/workflow-durable-task-step/

the user is miserably abandoned with no documentation at all on how to run a process. This in turn results in thousands of wasted hours around the globe.