OK..so you managed to choose an image that you'd prepared earlier and ran it through our favicon generator and you clicked the download link and have it saved on your computer hard drive. Well done....you're nearly there.
Now you need to upload it to the root directory of your webspace.
Most browsers will automatically detect and use the favicon.ico file, even on pages that are written in PHP, ASP, etc.
So your code could look like this:-
<head>
<link rel="icon" href="http://www.favicon.co.uk/favicon.ico" type="image/x-icon" />
<link rel="shortcut icon" href="http://www.favicon.co.uk/favicon.ico" type="image/x-icon" />
</head>
However, only the former is necessary, as "shortcut icon" will be treated as a list of possibilities by standards-compliant browsers (with "shortcut" being ignored, and "icon" used); while Internet Explorer will treat it as a single name ("shortcut icon"). The result is that all browsers understand the code. It is only necessary to include a second piece of code if one desires to offer an alternative image to modern browsers (e.g. an animated GIF).
Note: A file called favicon.ico and located in the document root directory will also be found by some browsers that do not process the link elements, even if it is not linked from anywhere on your site.
Now all you got to do is ask your viewers to bookmark your site
Add this code to your webpage:-
<a href="javascript:window.external.AddFavorite('http://www.favicon.co.uk/','Favicon Generator')">Bookmark This Page</a>