I've been watching Jeff Gibbons videos on Cube and they are very good. One thing I need to get clear on is send fx which he addresses on one video. He was trying to show how sends are different from regular fx like distortion on a guitar track.... he seemed to say that the send fx was used to color a PART of one track, maybe a few seconds of a track as opposed to a regular fx that colors the track for the whole length of a song...? but I didnt see him saving based on what time the send was in effect....have I got this right??

No, normally a Send does not add an effect in part of the song—in fact a Send is not an effect at all, it routes audio to an effect, though Cubase seems to present this a liitle differently, AFAICT.. Technically a Send is not an effect, a Send is a routing—it takes a copy of the signal in a channel and routes it to an effect in an Aux channel. The idea is that you can route Sends (copies) of multiple tracks into the same Aux effect (via a bus—a signal pathway), and apply different amounts of the same effect (most commonly reverb) to those various tracks. This is called a Send & Return setup, a type of parallel processing. I could point you to a video or two that illustrate the way it's normally done (in Logic or Pro Tools), but looking at one of our Cubase videos it seems to me that Cubase presents this in a kind of non-standard way..? I've attached the relevant video (below), and linked to the course (above)—maybe a Cubase guru can shed some light on the specific Cubase implementation ..