Question about placing the script and websites tracking


I have installed Piwik on my webspace and want to use it good.

I have placed the script only on te index page, I have a script on that page that if anyone visit the website it goes automaticly to the index page.

Am I thinking right or mus it be installed on every webpage?

Also have a question about people that are coming on te webite trough another website link.

If I want to see those people the dashboard says no rapport of this?

Thanks and greetings,