science fiction - How should I introduce new and complex technologies or tools?

I'm writing a Science Fiction book. While this book doesn't push reality very far, there are some new technologies and tools that I have added. One tool is used more frequently than all the others, and it has a very complex system (although there are other systems just as complex used somewhat less frequently in the story). For the sake of this question, we'll call it MYTO. The protagonist and the other supporting characters use MYTO on a regular basis, and an adequate understanding of it is critical to understanding and enjoying the story due to the frequent use of it. Normally, it wouldn't be a problem for me to introduce it and describe its functions. However, due to the complexity of MYTO and the systems surrounding it, I've found myself in a bit of a predicament.

I've written several drafts and concepts trying to describe MYTO and the systems it uses, and I've ruled out an all-at-once approach - it would take too long, and the reader would get lost and bored. Because MYTO is used in settings with high action, it is very difficult to describe it as I go along.

For a bit of a background, MYTO was a pre-existing technology based on other communication technologies used by the military and special forces in my story. My main character took it and modified it to create an improved version with several more functions and more polished functionality. I've tried to write this out, but it also gets very technical and boring, so I'm put back to square one.

How should I go about introducing the technology and its functions? Some of the functions can and have been explained throughout the story as needed, but they are lesser functions.

If any additional information is needed, please let me know in the comments.

Answer

Lauren gave the single most universal method - let me expand on that.

Note there doesn't have to be a literal character for the cabbagehead - a virtual one will do. Get some quotes from 'MYTO for dummies'. Get a cautionary work safety series series "Accidents resulting from and involving mishandling MYTO". Outright break the fourth wall having the omniscent narrator turn directly to readers (possibly in a condescending manner, for added irony if that's the tone).

If the system is complex, on top of brief summary of its function, if your publisher allows, you can throw a schematics in. A picture is worth 1000 words and things like these add flavor to sci-fi.

Last but not least, one of characters may be tasked with writing an instruction manual for cabbageheads, and we can follow their struggles with the daunting task - say, editor complaining "The readers won't understand complex words like 'shall', this must be changed!".

Including quotes and excerpts doesn't work well in movies, and not at all in TV shows, but it's a well-established technique in novels, so you can use it freely to circumvent the need to introduce another character or lower IQ of any of existing ones.