Just starting out and need advise for sub woofer connection

Hi I’m a rookie you guys are the big leagues so I am asking for your help.
I recently purchased a Canton K9 bookshelf speaker and stands. This speaker has a set of speaker cable posts for high and midrange and another set for the bass with jumper bars attached to the two sets of posts. Adrian the seller was so kind to include a Jamo c80 sub in my purchase. Which I hooked up as Paul McGowan the PS Audio poobah suggested by running speaker cable from my amp to the c80 cable posts for both left and right channels. Given this set up since both my main Cantons and the sub are receiving bass frequencies and both are playing them, this seems to be a duplication of effort and seems wrong. I was wondering could I, should I remove the jumper cable from my Cantons and attach my speaker cable to the terminals marked high and midrange? I assume doing so stops my Canton drivers from having to play bass frequencies. That Would free up these speakers from bass responsibilities? Is that a good thing? Should I do this ? and what must I be mindful about if I do this? Do I have to do anything to my subs crossover a knob reflects 40HZ to 200HZ  The canton literature mention a cross over at 3000 hz which to me woulld mean at the very least the difference between 200HZ and 3000 hz would be lost or should I forgetabout using the sub? The c80 also has what look to be RCA connectors titled Line left and right in and left and right out. Finally there is a LFE connection which is the same as the RCA left in. Thank you in advance for your help. Regards Scott