After you have them you need to unzip, and that's it. If you don't have any unzipping utility, search for WinZip, or pkzip. You should be able to find them as shareware.
Try www.downloads.com
To run Reducer, double click on it and it should start right up. If not double click GWBASIC and hit F3, type in reducer after the LOAD" line, and hit enter. You should then see "ok" and now you hit F2, and the program should start.
GWBASIC and REDUCER should be in the same folder.
To close exit from the Reducer menu and exit GWBASIC by typing the word system, and hit enter. Click close in the upper left corner.