How to Dearchive an archive file
If you have just downloaded an install or large upgrade file from the SMF Downloads page, you want to get the files out of it so you can use it. The .zip file is probably going to be easy to use on any desktop computer you are using. Windows PCs come with an unzipper built in. To use it, simply right-click on the .zip file, and choose "extract all" from the pop-up menu. You will see a dialog box telling you where the files are going to wind up. Make sure they go into a new directory with the same name as the zip file, because when you hit the Extract button, you'll have all of those files unzipped, unpacked, extracted, dearchived from that zip file exactly where that little box tells them to go.
If you are not planning to use the Windows built-in unzipper, you'll need to choose another archive manager that can handle standard zip files. Learning to use it should be pretty simple. Always make sure that you are happy about where the program is planning to put the unzipped files, so they are neatly stored in a subdirectory rather than mixed in with other files.