I’m a great believer in learning ‘hands on’ and perhaps using the Mach3 manual as a reference guide   https://www.machsupport.com/wp-content/uploads/2013/02/Mach3Mill_Install_Config.pdf
And, of course, the forum is here to help with any specific questions.

Just start making stuff and please post pictures of what you make, we all like pictures.

Tweakie.