Welcome back to the forum.....and no sweat over the wrong posting - it's now history.
There are a few way in which flexitrack can be joined to track sections......the one obstacle being the difference in height that the rail is above the surface on which the track sits. Here's a photo illustrating the difference:
This is from a small test track I knocked up out of leftover bits, etc. Note the gap under the flexitrack that will need to be addressed. Either lay the flexitrack on a sheet of cork or similar, or disguise the slope that you get going from one to the other. Whatever way you choose, it has no bearing on the way you join the tracks....
The simplest way....and probably the most expensive.....is to use the flexitrack to section track joiner ( http://www.tgauge.com/product/149/3/flexi-to-raised-track-joiner
Connecting without this special adapter is quite easy and can be done in two different ways....
Firstly, remove plastic from the end of the track section to expose sufficient of the two rails so that a flexitrack joiner can be slid on the end of the rails....and treat it as just another flexi to flexi joint. I've used that technique on The Bridge...as shown here:
Secondly, cut a flexi track connector in half and trim it down so the single track joiner fits onto the end of the rail on the track section....and the flexitrack will then join. Like this:
Note this photo shows use of a bit of track section that has the brass track joiner that I removed for the former method instead of half a joiner.
As far as cutting the track is concerned, I'd do a couple of practise cuts first so you get the hang of it. And there's no need to solder track joiners onto the track.....a push fit will suffice. The only soldering that can be done is to attach power to the underside of a track joiner, like I've illustrated in another thread in this section.