How to use Lead Scoring in CRM

We would like to introduce the use of Lead Scoring by including some logic that will depend on the value of fields in Contacts and Leads.

I am in doubt what module/function to use for this. So far I have found this:

1) There is an option to install a "Lead Scoring Module -> Score Criteria Builder", but it does not work and says that it is down!?

2) There is something called "Scoring Rules" under Automation in CRM.

3) There is a module called "Lead Score" in my ... menu in CRM

What should I use to setup Lead Scoring correctly? Also I would like to include data from the "Visitor Score" coming from SalesIQ!