Here is an overview of the terminology used with KeywordThinkTank and some basic principles of operation.
RELWORD - relevant word
Relevant word is pretty much self-explanatory. The jobs of type RELWORD return a list of words that are relevant to what you entered as input(s).
Those returned words (concepts) are used as seeds to create phrases that are relevant to your theme.
SUPERPHRASE - super phrase
Let's get a bit technical for this one.
{B,C,D} is a subset of {A,B,C,D,E,F,G}
{A,B,C,D,E,F,G} is a superset of {B,C,D}
"green metal widget" is a superphrase of "metal widget" is a superphrase of "widget"
If we determined that for our theme (theme that doesn't necessarily include the word widget in its declaration), the word "widget" describes a relevant concept, then getting phrases that contain the word widget that are still relevant to our theme is said to be building superphrases within that theme for the seed word widget.
Seed words
A word "widget" is a seed word for its superphrases like "metal widget", "cheap widget", "really nice widget", "widget trading", etc.
The most basic use case
Normally, you would start by using one or more RELWORD jobs to get a list of seed words. RELWORD jobs only need you to define a theme and leave the seed text box empty. As a matter of fact, a RELWORD job won't even start if you enter any seed words. The point of such job is to provide you with some possible seed options, not to request them from you.
For example, you define a theme "golf" just be entering "golf" as one input and get a list of seeds like "courses", "tee", "pga", "hole", "clubs", "tournaments", "woods", "instruction".
After that, you take those seeds and create SUPERPHRASE jobs by defining a more specific theme (possibly using multiple inputs) and supply the seed words.
To continue with this example, you would create a SUPERPHRASE job with an input "golf pga" and a seed word "pga". KeywordThinkTank will return a list of phrases relevant to "golf pga" that contain the word "pga" like: "pga tour", "pga championship", "pga of america", "senior pga championship", "pga tour schedule". Which are all relevant to golf.
You would continue creating SUPERPHRASE jobs for all seeds that you think are relevant to your niche. That's how you build a keyword list with KTT.
In all my demonstrations, I do one job at a time, and that is time-consuming. Normally, when I do my own research, I create multiple jobs so that more are being completed while I'm working with those that are already completed.
I would create my first RELWORD job to get a list of relevant seeds and then create 10 or so SUPERPHRASE jobs with some of those seeds. Once the first SUPERPHRASE job is complete, I start working on it, picking out phrases I want to keep.
By the time I'm done going through the results of the first SUPERPHRASE job, I have 4 or 5 other jobs completed.
Usually, just looking at the results of the first few jobs gives me more ideas about new RELWORD or SUPERPHRASE jobs to create, which I do right away. So with a normal work flow, I only have to wait for the first one or two jobs to complete. After that, I become the slowest point in the research.
What makes KeywordThinkTank different from other tools out there
There are plenty of great keyword research tools out there, and KTT is not a substitute for any of them. It was never meant to be a replacement of something like Google's Keyword Tool or Overture Inventory.
All those other tools help you build lists when you already know your keywords. KeywordThinkTank helps you brainstorm.
You can use KTT to create lists (as I've explained above), but the main benefit of using this tool is to help you find keywords/concepts/sub-niches/related themes that you might not have thought of on your own.
And it lets you do that without making your head explode. I don't know about you, but I can't spend more than couple of minutes just "thinking up" possible keywords on my own. I simply get tired.
This might sound silly, but I really get tired and decide to procrastinate instead of doing more work. If you've done keyword research on a niche with which you are not familiar, you probably know the feeling.
With KeywordThinkTank, I just mindlessly follow the results. The more results I see, the more ideas for new jobs keep popping into my head.
That's all there is to it -- follow the prompts and pick out what you want to keep.
Most of the time, once I'm done building up my lists with KTT, I plug them into one of the tools I mentioned above. So as I said, KTT is not a replacement for any keyword tool out there. It just make life much easier.