This entry is based on a post by someone other than me that appeared in forums.secondlife.com.
This entry assumes you are using Windows .
1. Download and install VisualC# Express from http://msdn.microsoft.com/vstudio/express/visualcsharp/.
2. Download TortoiseSVN from http://tortoisesvn.net/downloads and install it.
3. Create a folder called “dev” (w/o quotes) in C:\ (or in the root directory of some other harddrive).
5. Right click the dev folder, select SVN Checkout… from the context menu.
6. In the URL of Repository field, put in “svn://svn.berlios.de/libsecondlife/” (w/o quotes)
7. Click the Ok button. Files should start getting downloaded. When “Completed”, press Ok.
Now look inside the dev folder and the subfolders for sln files or proj files. Doubleclick them.
This should cause Visual C# to open and load the selected file.
On the right there is a window called the Solution Explorer. Right click an item labeled “Solution” and select Build.
Beyond this you have to stop following cookbook style instructions and start learning C#, read the libsecondlife documentation, read the code in the programs you just downloaded, and generally try to make your brain explode.
Reading the Second Life Terms of Service and putting your sense of empathy in gear would also be a good idea at this stage.