Once you install Vim you want to open the program called gVim in the start menu. Then you can File->Open the text file.

When you first open a file in gVim, it's ready to accept commands. i.e. typing things won't insert text into the file, rather vim will interpret any keys you press as a command to execute.

If you type a :, you should see text start to appear at the bottom of the vim window. That means it's interpreting what you type as a command to run. Type the first line I have above in its entirety exactly as it's written (be sure to include the : at the beginning), and press Enter. Nothing should really appear to happen, but stuff happens behind the scenes. Type the second line I have above and press Enter. Again nothing will really appear to happen.

The third line doesn't begin with a : . Still, type it exactly how I have it (capitalization matters). This time you should see stuff start to happen; when you type 1G the cursor may jump to a new location; when you press VG all the text should be highlighted, and when you press gq everything should be word-wrapped. Once you're done, File->Save like any other program.

If you press the wrong keys, you may throw vim into another mode and thigns may start getting screwy. If that happens I recommend closing vim and starting over (or else learning to use vim, but that may take a while).