Yeast Starter question

I just read https://www.homebrewtalk.com/f39/how-do-i-get-started-7908/#post74759 and Im brewing my 2nd brew, my first one used dry yeast my I just dumped into the primary and it work fine, but now this batch Im about to brew use White Labs liquid yeast, so I guess I need to make a start. After reading that thread I figure out making it is fairly simple, my question is how do you add it to the primary. I read an article http://hbd.org/uchima/yeaststart/yeaststart.html it states

You can either allow the starter to completely ferment out (usually 2-3 days), decant most of the liquid, and pitch just the slurry; or you can pitch the entire starter into your batch of beer, while it is actively fermenting (typically after a day or so). Both approaches have their advantages. Letting the starter ferment out and decanting means you're not adding a lot of "foreign" wort to your batch of beer. But pitching while it is active will result in a shorter lag time.

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So it looks like I have 2 options of adding the starter, but I have no idea what "pitch just the slurry" means? And of the two options which is better prefered?

Decant - pour off the liquid on top and what's left is the thick slurry, which contains yeast.

Thank you, any suggestion on whats better?

I pitched a batch of washed yeast without a starter to a 1.050 pale ale Saturday. I ptiched a 1L starter in active fermentation of the same yeast to an IIPA yesterday. They both started fermenting about 3 hours after I ptiched the IIPA.
With the starter I pitched the whole thing, the other I poured off most of the liquid, mixed it up, brought it to room temp, and pitched.

I make my starter about 3 days before brewing, make sure to give it a good swirl a few times each day, and then put it in he fridge 12-24 hours before pitching to make sure it all flocs out. As my mash water is heating, I pull it out of the fridge to let it readjust to room temp. When it's time to pitch, I pour the majority of the starter wort off, leaving just enough to swirl up the slurry, and then pitch that. Pitching the right amount of yeast has made a noticeable difference in my fermentations and the resulting beer. The biggest difference being that my beer just tastes cleaner.

Fwiw, I use the mr. Malty calculator religiously to determine my pitch rates.

I don't think that it makes a difference. I usually pitch while my starter is actively fermenting because I always wait till the last minute to make my starters. If it does have enough time to ferment out then I pour off the wort. It doesn't make much of a difference.

i think it depends on what the beer is. for ales, i dont really worry about whether i decant or not, that all depends on what kind of time i had (sometimes i forget to make the starter early enough haha) but if its a lager, your going to be making a much larger starter and probably growing at room temp, making all kinds of off flavors you dont want in the beer. for lagers i would most certainly give the starter enough time to fall out so you can pour off the starter wort