docs: add usage example with screenshot to readme

README.md

@@ -33,3 +33,64 @@ ShinyPDF is a modern open-source .NET library for PDF document generation. Offer
 ## Let's get started
 
 Begin exploring the ShinyPDF library today.
+
+Install the [NuGet package](https://www.nuget.org/packages/ShinyPDF):
+
+```bash
+dotnet add package ShinyPDF
+```
+
+On Linux, also add the native assets for SkiaSharp and HarfBuzzSharp:
+
+```bash
+dotnet add package SkiaSharp.NativeAssets.Linux
+dotnet add package HarfBuzzSharp.NativeAssets.Linux
+```
+
+Then describe your document with the Fluent API and generate the PDF:
+
+```csharp
+using ShinyPDF.Fluent;
+using ShinyPDF.Helpers;
+using ShinyPDF.Infrastructure;
+
+Document.Create(container =>
+{
+    container.Page(page =>
+    {
+        page.Size(PageSizes.A4);
+        page.Margin(2, Unit.Centimetre);
+        page.PageColor(Colors.White);
+        page.DefaultTextStyle(x => x.FontSize(20));
+
+        page.Header()
+            .Text("Hello PDF!")
+            .SemiBold().FontSize(36).FontColor(Colors.Blue.Medium);
+
+        page.Content()
+            .PaddingVertical(1, Unit.Centimetre)
+            .Column(x =>
+            {
+                x.Spacing(20);
+
+                x.Item().Text(Placeholders.LoremIpsum());
+                x.Item().Image(Placeholders.Image(200, 100));
+            });
+
+        page.Footer()
+            .AlignCenter()
+            .Text(x =>
+            {
+                x.Span("Page ");
+                x.CurrentPageNumber();
+            });
+    });
+})
+.GeneratePdf("hello.pdf");
+```
+
+The result:
+
+<img src="./docs/img/example-hello-pdf.png" width="400" alt="Generated PDF page with a blue 'Hello PDF!' heading, a paragraph of placeholder text, a gradient placeholder image and a 'Page 1' footer" />
+
+`Placeholders` generates sample text and images, which is handy while designing a layout. More examples are in [src/ShinyPDF.Examples](src/ShinyPDF.Examples).