Choosing the suitable scripts for your site is the first and important phase of installing any script. It is time consuming to try several scripts by installing and testing them and you may find after hours of struggling, that the script is not working. When I was a beginner, I installed a huge script and configured it and the script started running successfully. But very soon I found that I was unable to enjoy many of its functions because of a Perl version conflict. The script author informed me that it can run only on a server, which has Perl 5.004, or above, but our server had only version 5.003. That was a bad day for me. So you should be really careful to learn your server capabilities like Server Side Include support, Perl version and of course the cgi-bin permissions. (We can learn about this later).
You can decide if a script is good for you by looking at
If you are lucky you can find a scriptwriter who will install it free for you. Some companies offer the service of installing scripts in your web site for a fee of $25-$100.
If you are satisfied with the information you have discovered about a script, then you are ready to download it. Once downloaded you can use any of the unzip utilities to extract the downloaded file. I use Winzip, as this can unzip most of the files. Move the unzipped files into a separate folder in your local hard drive. Among the unzipped files, you may find some .aspl files. You can evaluate the .aspl file and find whether the script is making use of it as a template. If it is, then I can say you are lucky enough to be able to edit and customize the appearance of it according to the design of your web page.