ClanLib comes in two editions, 32 bit (win32) and 64 bit (x64). We recommend using 32 bit version unless you have very specific needs.
ClanLib relies on some other libraries like libpng and zlib. These are required to be downloaded unless you've already done so for a previous version of ClanLib. (Updated 23.02.2012)
Jump to the documentation - it has installation guides and documentation on various sections of ClanLib. Note, if you want to look at the ClanLib Examples, you also need to download the source package.
If you are developing using Visual Studio 2010, download the Visual Studio 2010 Plugin that lets you create new ClanLib projects easily by using File->New->Project and selecting the ClanLib wizard.
If you are updating from an older version, please read about the breaking changes.