removing spool from reel or taking spool apart and srevice. the top of spool unscrews counter clock wise, remove small screw inside top and unscrew nut. the bottom cover is just a press fit so push the top shaft down and it is apart.
The knurled knob is also independent of the tension dial. You should not be twisting the tension dial like a normal reel. You only turn the knurled knob. This way the tension stays the same when you change spools.
You can see a close up of the top of the reel in this pic from another site. That little small knob on the top is what you twist, not the entire tension knob. I hope that make sense to you.