Update README with docs on how to use

Author: augustoproiete

README.md

@@ -1,5 +1,53 @@
 # Serilog.Enrichers.ExcelDna [![NuGet Version](http://img.shields.io/nuget/v/Serilog.Enrichers.ExcelDna.svg?style=flat)](https://www.nuget.org/packages/Serilog.Enrichers.ExcelDna/) [![License](https://img.shields.io/github/license/caioproiete/serilog-enrichers-exceldna.svg)](LICENSE)
 
+Enriches [Serilog](https://serilog.net) events with information from your [Excel-DNA](https://excel-dna.net) Add-in.
+
+### Getting started
+
+Install the [Serilog.Enrichers.ExcelDna](https://www.nuget.org/packages/Serilog.Enrichers.ExcelDna/) package from NuGet:
+
+```powershell
+Install-Package Serilog.Enrichers.ExcelDna
+```
+
+To apply the enricher to your logger configuration:
+
+```csharp
+var log = new LoggerConfiguration()
+    .Enrich.WithXllPath()
+    // ... other configuration ...
+    .CreateLogger();
+```
+
+The `WithXllPath()` enricher will add an `XllPath` property to produced events.
+
+### Included enrichers
+
+The package includes:
+
+* `WithXllPath()` - adds `XllPath` based with the value of `ExcelDnaUtil.XllPath`
+* `WithExcelVersion()` - adds `ExcelVersion` with the value of `ExcelDnaUtil.ExcelVersion`
+* `WithExcelVersionName()` - adds `ExcelVersionName` based on `ExcelDnaUtil.ExcelVersion`
+* `WithExcelBitness()` - adds `ExcelBitness` based `Environment.Is64BitProcess`
+
+### Example of an Excel-DNA add-in using Serilog with this sink
+
+In the [sample](sample/) folder, there's an example of an Excel-DNA add-in that uses Serilog for logging to the `LogDisplay` of Excel-DNA using this sink, and apply the enrichers described above.
+
+![Seq showing properties from Serilog.Enrichers.ExcelDna](assets/serilog-enrichers-exceldna-nuget-seq.png)
+
+### Excel-DNA configuration for packing with `ExcelDnaPack`
+
+In order for the Excel-DNA enricher to work from an add-in that was packaged using the `ExcelDnaPack` utility, you need to include references to `Serilog.dll` and `Serilog.Enrichers.ExcelDna.dll` in the `.dna` file of the add-in:
+
+```xml
+<DnaLibrary Name="My Add-In" RuntimeVersion="v4.0">
+  <ExternalLibrary Path="MyAddIn.dll" ExplicitExports="false" LoadFromBytes="true" Pack="true" />
+
+  <Reference Path="Serilog.dll" Pack="true" />
+  <Reference Path="Serilog.Enrichers.ExcelDna.dll" Pack="true" />
+```
+
 ---
 
 _Copyright &copy; 2018 Caio Proiete & Contributors - Provided under the [Apache License, Version 2.0](http://apache.org/licenses/LICENSE-2.0.html)._