Although I'm only a princess (in my own mind), you can do it either way. It depends on how far you have to go with the carrying thread. You need to secure the threads at the end of the first motif and the start of the next. If you take 3 or 4 tiny stitches you can just clip the threads as you go. If you want to actually tie off your starts and stops and bury the threads, then you can carry them and cut, tie & bury when you are all done and off the frame. If you carry the threads, you will have to have all your sashing quilting done before the motifs so that you don't stitch over the carried threads.
Although I have a zillion quilting books, I've been disappointed with the long arm books I've purchased. Learned more on this board. Do a search on your question, if you don't find an answer, then post. lots of help.