How to get started: Making a GUI app with Projucer

The tutorials are pretty good, I think.

In-case these are not what you found, you can find them here - https://juce.com/learn/tutorials

Probably the easiest one to start with is
https://docs.juce.com/master/tutorial_new_projucer_project.html

Then https://docs.juce.com/master/tutorial_manage_projucer_project.html

Then https://docs.juce.com/master/tutorial_create_projucer_basic_plugin.html

Then https://docs.juce.com/master/tutorial_code_basic_plugin.html

Good luck!