There are a number of classes of HELICS users:
New users that have little to no experience with HELICS and co-simulation in general
Start with Installation
Read the Fundamental Topics
Try the Examples
Intermediate users (Modelers) that have run co-simulations with HELICS using simulators in which somebody else has done the simulator integration with HELICS.
Review Fundamental Topics as needed
Look over the Advanced Topics to see which features of HELICS may be most useful for your analysis.
Experienced users (Integrators) that are incorporating a new simulator and need to know how to use specific features in the HELICS API
Developers of HELICS who are improving HELICS functionality and contributing to the code base
See the Developer Guide