An Object Event Simulation (OES) example model. You can download and inspect its code from the OES GitHub repo.
Process Design Model

A Service Desk System as an Activity Network

This minimal Activity Network model consists of two nodes: an initial event node for recurrent "CustomerArrival" events and an activity node for "Service" activities, which require a service desk as a (performer) resource. These two nodes are connected with a Resource-Dependent Activity Scheduling (RDAS) arrow.

Simulation Log
StepTimeCurrent EventsSystem StateFuture Events