To use Exselt you will need a license key. After installation you can unlock the Exselt XSLT 3.0 processor with a temporary or permanent license key, which you can request here.
You can download the Windows version of Exselt below. Others have kindly provided instructions for installation on Linux or Mac OS X, see the page on installation instructions for details on those.
Exselt for Windows
If you plan on using Exselt on different processor architectures, we suggest you download the AnyCPU version. There specific CPU versions have a small startup performance improvement, which you can benefit if you target only x64 or x86 machines.