How do I setup Apache SpamAssassin?

Im not trying to do anything fancy, just setup spam assassin and understand the settings. I started by going into Cpanel and enabling spam assasin. I saw the spam box feature and think I understand what that's for. I don't want the spam sent to another account so I left it disabled.
Next I looked at the spam assassin configuration settings.
Blacklist_from- I understand this
Required_hits- Im pretty sure this means the number of identical messages received before they start getting marked as spam.
Rewrite_subject- I assume I want this set to 1, how could it stop spam set to 0?
Score- Im completely baffled by this setting
Subject_tag- I understand what this does.
Whitelist_from- I understand what this is for

To try and understand the rest, I went to the spamassassin.org website and took a look at the wikki. This left me even more confused, I was unable to find any information on the above. I have always had trouble getting useful info from Wikkis, so this is probably my own fault.
Next I checked the Cpanel documentation on this site. It failed to explain anything about the score setting.
Next I searched this forum for spam assassin score. After reading the results, I am even more confused. I still dont know how to use the feature or exactly what it does. If someone could fill in the holes in my knowledge of the basic settings, I would apreciate it.
Thanks

 

Yes I read all that on the configuration page within Cpanel. In my version the option you are referring to is called "required_hits". Unfortunately that is not the option I am referring to or having trouble understanding. The options that have me baffled are a little ways below that option(required_hits) in the version im using.
There are five fields im confused by are called "score". The explanaition for these fields is as follows:

Im sure that explanation makes perfect sense if you already know how to use it, however it confuses the heck out of me. Could someone dumb it down for me. What would I put in these 5 fields for example and why? how would it affect the incoming email?

 

Thanks,
I think I have it setup correctly. I set the Required_hits score to 8.
I ran a few tests with words like viagra, but it doesn't tag them.
I looked in the file 20_drugs.cf to see what words are there.
I tried "dose" in the body and all kinds of offensive words, but it doesn't tag it as spam.
rewrite_subject is set to "1". Am I missing something? Is is spamassassin broke?

 

Thank You ccccanada that was Immensely helpful!

 

Still cant get it to tag any spam.

I added DRUG_ED_ONLINE 8.0 to the first score field. I left the rest of the score fields blank. If I understand what I am reading, adding DRUG_ED_ONLINE 8.0 to the score field while my Required_hits is also set to 8.0 will cause the words "Fast Viagra Delivery" to flag the message as spam every time.
It doesn't work.
Am I doing it wrong. How can I test this to see if it's working?

Current settings are exactly as follows:
Spam Assassin: Enabled
Spam Box: Disabled
required_hits: 8.0
rewrite_subject: 1
score: DRUG_ED_ONLINE 8.0
score:
score:
score:
score:
subject_tag:*****SPAM*****
blacklist_from: (are all blank)
whitelist_from: (are all blank)

With this setup I expected the phrase "Fast Viagra Delivery" would get tagged as spam every time. It doesn't.

This is from the message header of a message with "Fast Viagra Delivery" in both the subject and body. The message was not tagged as spam.