1.2Flow

A Mule flow is an executable sequence of components.

Example:

HTTP Listener
      ↓
Transform Message
      ↓
Salesforce Query
      ↓
Choice
      ↓
Salesforce Upsert
      ↓
Transform Message

Conceptually:

async function createCustomer(request) {

    const customer = transformRequest(request);

    const existing =
        await salesforce.query(customer.email);

    if (existing) {
        return await salesforce.update(customer);
    } else {
        return await salesforce.create(customer);
    }
}

Mule represents this graphically in Anypoint Studio/Code Builder and underneath as XML.

Something approximately like:

<flow name="customer-flow">

    <http:listener
        config-ref="HTTP_Listener"
        path="/customers"/>

    <ee:transform>
       ...
    </ee:transform>

    <salesforce:query
        config-ref="Salesforce_Config">
       ...
    </salesforce:query>

</flow>

Don't be intimidated by the XML.

The XML is simply configuration describing the pipeline.