docs: update readme with setup instructions

* readme updooted

* global install

Author: Andrewjeska

README.md

@@ -4,6 +4,35 @@
 
 Seam
 
+## Local setup
+
+For C# development, you will need to install `dotnet`
+
+Download the installer [here](https://learn.microsoft.com/en-us/dotnet/core/install/macos)
+
+Then, you may need to create a symlink
+
+```bash
+ln -s /usr/local/share/dotnet/dotnet /usr/local/bin/
+```
+
+Finally, install csharpier
+
+```bash
+# if you don't yet have a .config/dotnet-tools.json file
+dotnet new tool-manifest
+
+dotnet tool install -g csharpier
+```
+
+## How to update the SDK
+
+Once you've completed all the steps in the Local setup section, you can run the following command to update the SDK
+
+```bash
+npm run generate
+```
+
 ## Installation
 
 Use [nuget](https://www.nuget.org/packages/Seam) to install.