readme: Explain implementation steps

Author: NickVolynkin

README.md

@@ -4,10 +4,11 @@
 [![](https://img.shields.io/badge/💬_Leave_Feedback-feecdd?style=flat-square)](#does-this-example-address-your-development-requirementsobjectives)
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-# DevExpress VCL Reports—Generate a PDF Report Using a Headless (non-GUI) application
+# DevExpress VCL Reports — Generate a Report Using a Headless (non-GUI) Application
 
 This example uses the DevExpress VCL Reports components to generate a PDF report using a command line application.
-The example demonstrates the capabilities of VCL Reports for producing reports in backend applications, webservers, or command line applications, all without the need for a GUI.
+The example demonstrates the capabilities of VCL Reports for producing reports in backend applications, Windows services,
+or plain command line applications, all without the need for a GUI.
 
 The example includes projects for both [Delphi](./Delphi) and [C++Builder](./CPB).
 
@@ -25,16 +26,95 @@ See: [DevExpress Reports Prerequisites](https://docs.devexpress.com/VCL/405773/E
 By following the steps outlined in this example, you'll create an application that produce the
 [DevExpress VCL Reports](https://docs.devexpress.com/VCL/405469/ExpressReports/vcl-reports).
 
-### Prepare a Template Report Layout
+### Step 1: Initialize a Report and Import a Report Layout
 
 An application needs a template report layout, created in the [Report Designer](https://docs.devexpress.com/VCL/405469/ExpressReports/vcl-reports).
 
-You can [store a report layout in a REPX file](https://github.com/DevExpress-Examples/vcl-reports-store-layout-template-file)
-or [in a database](https://github.com/DevExpress-Examples/vcl-reports-store-layout-template-database).
-
-This example loads a report layout from the [`Order.repx`](./Order.repx) file.
-
-### 
+You can [import a report layout from a REPX file](https://github.com/DevExpress-Examples/vcl-reports-store-layout-template-file)
+or [read a layout from a database](https://github.com/DevExpress-Examples/vcl-reports-store-layout-template-database).
+
+The current example imports a report layout from the `Order.repx` file.
+
+**Delphi:**
+```pas
+// Step 1: Create a report instance and load the report layout
+AReport := TdxReport.Create(nil);
+try
+    // Set an internal report name (does not affect the exported PDF content and file name)
+    AReport.ReportName := 'OrderReport';
+    // Load the report layout from the specified file
+    AReport.Layout.LoadFromFile(ALayout);
+    // ...
+finally
+    AReport.Free;
+end;
+```
+
+### Step 2: Create a Database Connection
+
+A VCL Report requires a source of data, which is usually represented by a database connection.
+The current example is using SQLite with the Northwind example database stored in `nwind.db`.
+
+```pas
+// Step 2: Create a database connection
+AConnection := TdxBackendDatabaseSQLConnection.Create(nil);
+try
+    // Assign a database name matching the name specified in the report layout
+    AConnection.DisplayName := 'NWindConnectionString';
+    // Assign a connection string to use the local SQLite database
+    AConnection.ConnectionString := 'XpoProvider=SQLite; Data Source=..\nwind.db; Mode=ReadOnly';
+    // ...
+finally:
+    AConnection.Free;
+end:
+```
+
+### Step 3: Define Report Parameter Values
+
+A report layout may have one or more parameters.
+VCL Reports use parameters to modify database queries and produce different reports using the same layout and data.
+For example, `Order.repx`has a single `OrderIDParameter` used to produce reports on customer orders with given Order IDs.
+
+To modify parameters, load them using the `LoadParametersFromReport` method and assign values to members of the `Report.Parameters` list:
+
+**Delphi:**
+```pas
+// Step 2: Define Report Parameter Values
+AReport.LoadParametersFromReport;
+// Set the value of the "OrderIdParameter" parameter in the report layout
+for AReportParameter in AReport.Parameters do
+    if AReportParameter.Name = 'OrderIdParameter' then
+        AReportParameter.Value := AOrderID;
+```
+
+To learn more, follow the guide: [VCL Backend: Supported Database Systems](https://docs.devexpress.com/VCL/405703/ExpressCrossPlatformLibrary/vcl-backend/vcl-backend-supported-database-systems).
+
+### Step 4: Export and Save to a File
+
+Once you have configured a report and a data source, and defined report parameters.
+you can export a report to one or more formats.
+
+The current example exports a PDF report and saves it to a file:
+
+**Delphi:**
+```pas
+// Step 4: Export a report to PDF
+AStream := TMemoryStream.Create;
+try
+    // Export a report to PDF format and save it to a memory stream
+    AReport.ExportToPDF(AStream);
+    // Write the content of the memory stream to a file
+    AStream.SaveToFile(AOutput);
+    Writeln('Report saved to: ', AOutput);
+finally
+    AStream.Free;
+end;
+```
+
+### Optional: Exporting Multiple Reports
+
+Headless approach allows you to efficiently produce multiple reports using the same layout and data, but different parameter combinations.
+You can repeat steps 3 and 4 for each parameter combinations.
 
 
 ## Files to Review