Oh, thank you so much for the tips!
I do remember "Snap to Grid" being mentioned in Lesson #1, and read the full article on that link provided in Lesson #3 - I'm just not understanding how to work it or work with it.
The linked article said it could all be done in the editor just by changing the Z access in the editor to the degree of angle from the starting section. (90, 180, etc.) - the image he posted showed all Y & X access set to zero and the Z access on the right set to 90.
I tried that and the piece ended up inside the starting section. So I ended up moving it manually - all of it. The numbers on the X axis were becoming astronomical for some odd reason. Did I mention I never took geometry? Urg!
For the first five section (first section through the first two attaching 90 degree angle pieces) I thought I was doing great. After that things got a little ... off. I decided (for some reason unknown to me) to do the two 4-way pieces next. That is when everything started going all to H. It was grueling, but I finally got it where it looked pretty decent. I put the outer sides on and began doing an inspection for tiny gaps or overlays before moving any further. (moving pieces at a rate of 25% so as not to over- or under- correct). Gaps could not be seen from some angles, but were glaringly obvious at other angles.
The "Snap to Grid" was on through-out all this. Am I supposed to see a grid? Because I didn't.
So finally I had everthing looking immaculate ... till I tried to put in the last piece, the "LThree-Way." It was way too small to fit in the large slot left for it, had huge gaps on all three connecting sides. I fiddled and fiddled and nothing worked - so I started from the beginning again, thinking that had to be where the original error was that was leaving a larger gap on just one piece of the Basement...but if that was the case, why was everything else fitting so perfectly? I scoured the list for another piece that may work there, none did.
After that, the more I fiddled the worse it got. Finally I got everything back to looking great, smooth as glass everywhere - and once again the "LThree-Way" was like 2X too small for the hole left for it to slide into.
Rather than pull my hair out screaming, I made the last piece 1.7X its original size (and it still didn't fit) - and shut down the CS. .
I know I can't leave one overgrown piece in there - but I'm out of guesses on what I've done wrong and how to fix it.
HEEEEELLLLPPP !!! Please?