On the EnergyPlus website is a link for support and training. There you will see that GARD Analytics and Big Ladder Software offer training workshops, which are either public with a standard list of topics covered or in-house at organizations that would like a customized training experience. These would be great starting points for beginners, since they outline the structure of EnergyPlus and will help you avoid common modeling mistakes.
I can only offer more info about Big Ladder's training workshops, since I work for the company as a trainer. The public workshop lasts 2 full days and covers intro topics (format and syntax for input files and output files, simulation steps, etc.) in the beginning up to intricacies of plant and air systems by the end. Throughout the workshop, we offer tips for modeling best practices that will make your life easier and have hands-on exercises where you gain experience with multiple modeling topics in EnergyPlus. Our ultimate goal is to have students leave with an organized mental model of how input objects (the individual building blocks of EnergyPlus input files) interact with each other. This arms students with the ability to debug warnings and errors in their models after the workshop.
For some self-teaching, the EnergyPlus website also has links to university course material on EnergyPlus. This material is meant to be used by professors to create lesson plans for the course.
You can also review the EnergyPlus documentation, either in PDF form when you install each version or in web form. I would recommend starting with EnergyPlus Essentials to understand more background information about building energy modeling in general as well as EnergyPlus as one building energy simulation engine. Once that is covered, you can review more details in the Input Output Reference (lists all EnergyPlus objects, their input fields that can be defined, and their output variables that can be reported) and the Engineering Reference (covers details of calculations and assumptions used for simulations).
A video resource for training is Energy-Models, although you have to pay for access to their video lessons. You can also search YouTube for EnergyPlus, where multiple users have been kind enough to upload tutorials.
Finally, the EnergyPlus Helpdesk is moderated by members of the EnergyPlus development team that updates and improves the source code. You may find helpful information there as well.
I hope this helps!
