In a business process, an event represents a specific occurrence or trigger that causes the process to start, stop, or change its course. Events can be internal or external to the process and can be initiated by a variety of sources, such as human actions, system events, or environmental conditions.

Events can be categorized into three main types:

1. Start event: This type of event initiates the process and marks the beginning of its execution. Examples of start events include a user filling out a form, a customer placing an order, or a system timer expiring.
2. Intermediate event: This type of event occurs during the execution of the process and can trigger various actions, such as sending a notification, updating a database, or waiting for a certain condition to be met. Examples of intermediate events include receiving an email, reaching a certain deadline, or encountering an error.
3. End event: This type of event marks the completion of the process and signifies its successful or unsuccessful execution. Examples of end events include delivering a product, canceling an order, or encountering an error that cannot be resolved.

Events are important in business process modeling because they help to capture the dynamic nature of business processes and enable the process to respond to changing circumstances or inputs. By identifying the events that trigger the process and the actions that should be taken in response, a business can optimize its processes to be more efficient and effective.

Add a Start Event

A start event represents an interaction that begins or starts a process.  

1. From the Components tab, select the Event button
2. Click where you would like the Event to appear in your diagram
3. From the Properties Inspector:
   • Change the Type of the Event to Start
4. Name the event e.g. Start

When the same process can be started for different reasons, it is correct to have multiple start events.

Add an End Event

An end event represents an interaction that completes or ends a process. When you are ready to finish your flow diagram, add an end event. 

1. From the Component tab, select the Event button
2. Click where you would like the Event to appear
3. From the Properties Inspector, change the Type of the Event to End

Adding a Wait for Input or Output Event

Along with Start and End events you can also have events occur part way through your business process. These are used to indicate that the process is either waiting on or sending information from outside the process. They are added to the process map in the same way as a Start or End event.

How or when does the Event occur?

Events occur because something happens outside of the process and needs to interact or the process needs to send information outside of the process. When you are modelling the process for technical reasons you may wish to capture more information on how or when the event occurs. You can select from

• Message received - used when another system sends a message
• Message sent - used when the process needs to send an electronic message to another system
• Timer expired - used when either a specific time is met or a time period passes
• Signal broadcast - used to send broadcasts to anywhere in the process
• Signal detected - used when another part of the process sends a broadcast signal
• Condition met - the event will be satisfied and the process will continue when the condition is met
• Any one of several events - used when the event could occur for a number of reasons, but the further classification of the event is not required
• Multiple events together - used when more than one event is required to allow the process to continue
• Called by a specific process - used to make the connection to a specific process
• Escalation request  - used in BPMN to indicate that a parallel set of activities should be performed as part of an escalation procedure. For example if an activity has not been completed in an appropriate timescale, then the activity should continue being processed, but an escalation procedure may be invoked to better enable the management of the exception.
• Compensation request - used in BPMN to indicate the activities that should be performed in order to undo the consequence of earlier activities. For example if a process removes funds from an account and then the process is not able to complete a compensation request could be used to specify that the funds are re-applied to the original account.
• Error report - used when the activity cannot be performed and the situation is considered an error. For example if a customer process enables change of address, then the process could be configured to check that the customer exists before performing the change of address or it could be that the customer not found is an error report.
• Terminate all activities - most commonly used when a process has parallel paths and one path has reached the end and any remaining parallel activities should stop.
• Cancellation requested - used in more technical BPMN when the process is executable
• Return to specific calling process - passes control back to a specific calling process