In window, select the message or messages to be uudecoded. You can use any convenient filename and location - Eudora suggests the email's Subject line as a filename. Open the file saved from Eudora using a uudecoding program, which will recover the original file. Open the uudecoded file with an appropriate program, for example Word for .doc or word processor files, a JPEG or GIF viewer for .jpg or .gif file, etc. If the uudecoded file is an unknown executable binary, be suspicious and take care if it is not from a known and trusted person.
Some applications are able to uudecode automatically.