To get started, follow these steps:

1. Download and run setup for your machine (32-bit or 64-bit)
2. Open the File Association Manager (under the File Metadata entry in the Start menu, if you still have one)
3. Scroll down to and select the extension or extensions of your choice from amongst those that currently have no handler (.txt is a good starting point) and click Add File Meta Handler
4. Open an Explorer window and select a file of the chosen type. Metadata edit entries should appear in the Preview Panel at the bottom of the window.
5. If nothing shows up, try logging off and on, or equivalently, killing all instances of explorer.exe and restarting it. Sometimes it doesn't catch on to its new powers immediately.
6. If all is well, great! But If you're having trouble, check the FAQ, and search previous Discussions. And if that still doesn't get you going, open a new Issue and we'll try to help. Or, if you don't like all those dire download warnings (and I don't), grab the source, read, build and then goto step 1. How did we ever trust anything before FOSS?

I will close with a handy tip for Windows 8 and Windows 10 users. Because Explorer remembers the settings for an extension when it reads them, it is sometimes necessary to restart Explorer after having made changes using the File Association Manager. In Windows 8 and 10, Task Manager makes this really easy. If you select Windows Explorer in the list of running Apps, the button at the lower right will restart all instances of Explorer at a stroke: