Some of the scripts you want to install on your host (for example the php autoresponder) will require you to set up a cron job. This is a command that runs automatically at specified period of time - once per day, once per hour, each 5 minutes, each Monday etc.
Fortunately most shared web hosts are running Cpanel which makes setting up a cron job a very easy task. It's not going to take you more than 5 minutes. We'll cover using the "Standard" procedure, because it's easier to understand and follow.
Enter the Cpanel control panel of your website (usually by loading http://yourdomain.com/cpanel in the browser) and locate the "Cron Jobs" icon. If you can't see it immediately, press Control+F and type "cron". Your browser will locate the icon for you. Click on it and see the following screen:
Click on "Standard" button to load the standard Cpanel cron job interface:
There are just four little things you have to do and I have numbered them on the screenshot:
1. Enter email which to receive the cron job output (optional). This step is completely optional - in most cases you will not really care to receive email each time when the scheduled script runs. However this field is useful for other reason. In most cases Cpanel has pre-filled it with your account username (in my case it is pimteam). You will need it in step 2, and in case you don't know what exactly it is, Cpanel puts it in front of your eyes.
2. Enter the command to run.
Important: On many Cpanel based servers instead of the command shown below you can simply enter command like this:
This command will work for scripts that allow running from the web. Of course replace "http://yourdomain.com/sender.php" with the URL of your script, as you would access it from the browser. You can just go ahead and try. If it works for you you can jump to step 3 ("Schedule when the command should run").
Most often you will be running a PHP or other script like in the example I have given. Let's dissect this example command in several parts:
php -q /home/pimteam/public_html/sender.php > /dev/null
3. Schedule when the command should run. The options providedby Cpanel here are easy to understand. You can schedule the command to run in specific days or every day, every month or just some month, at specific hour(s) and minute(s) or just at 3.30 AM for example. You can select several options from each selection box by holding the Control key.
4. Save Crontab. Hit this button to save your changes. That's it :)
Most probably your hosting doesn't use Cpanel, but some other software. It's also possible that you have opened some other admin panel of your site but not the hosting control panel. In both cases you can first search for information about setting up cron jobs in the help files given by your hosting provider. You can also directly contact the support and ask for help.
If you are still confused, just follow me on Twitter and ask your questions!