A lot of it is information retrieval.

You look up the key words with Google like parts sources and prices

In the above example, I feared a mistake after I posted, so I Googled Walbro and looked at the manual.

I think I'm right from looking through the explanations in the PDF manual

So I posted a link to the manual also.

Also I did a casual on the carb number but didn't immediately pull up any applications for that number so went on to other things relative to the subject of the post.