How or where do I download Internet Explorer for Mac OS 10.7.5?

Internet Explorer is only supported on Windows, so you can't use it on OS X. There are a lot of browsers like Safari, Firefox or Chrome for Mac, so try them. If you need Internet Explorer, you have to install Windows on your computer. See > https://discussions.apple.com/docs/DOC-3321

IE was a PPC application that has not been supported for nearly six years. Even were you to find it, you could not run it on your system.

You can use Safari's Develop menu to change the User Agent to IE. You can add the Develop menu via the Advanced preferences of Safari preferences.

You're welcome