To start with Roslyn, take a look at:
A tool for converting an sample C# program to syntax tree API calls. The tool itself can be found here.
An easy way to view the Roslyn source code can be found here.
To start tinkering with Roslyn you will need the following NuGet packages:
The C# and VB compilers - Microsoft.Net.Compilers
. To install it you can run the following command in the Package Manager Console:
nuget install Microsoft.Net.Compilers
The Language APIs and Services - Microsoft.CodeAnalysis
. To install it you can run the following command in the Package Manager Console:
nuget install Microsoft.CodeAnalysis
Additionally it is a good to install the .NET Compiler Platform SDK Templates, that can be found here. This will get you:
View -> Other Windows -> Syntax Visualizer
), which is extremely usefully for examining the syntax tree of existing code.