What bike are you using now??
It's it is a kapchai, the bike has a centrifugal clutch so it would unload the drivetrain automatically and engage gradually.

However for clutch bikes, you can still upshot or downshift without a clutch. You just need to unload the drivetrain a split second before shifting. Clutch-less upshifts are easier to do, downshifts needs quite a bit more finesse. Some fancier bikes have autoblip feature on the quickshifter to help downshifts.

If you fark up a clutch-less downshift you might lock up the rear if you don't have a slipper clutch on your bike.

no need to overcomplicate things.

what ur talking about is rev matching. there is no actual need to master it as this is more of a motorsports thing. they do it to minimize or eliminate the jerk that happens when u downshift while going high speed into a corner. that jerk could make the bike a lil unstable in high speeds and especially at a lean... in kapchai speeds, not so much. although good to master, no real need.

for cars, its usually referred to heel n toe. feel free to google... ull see that most people dont even practice this in their daily drives and just downshift like normal.

as for taking care of the clutch... bleh... the clutch is more resilient than u think. even with downshifting like normal (ie throttle to 0, then downshift n release gear lever) or even abusing it, the clutch will probably last longer than the engine itself unless u screw it up somehow like using car engine oil instead of bike engine oil (which can burn the clutch).

but if u really wanna know, the correct procedure is....
* throttle to 0
* press gear lever

* blip the throttle to the right rpm
* release gear lever

all this basically has to be done in a split second between them - its as if everything is done simultaneously...its that quick. not that hard to do but will take practice to master especially blipping the throttle to the right rpm as u may under rev or over rev.

i ride a z900 (which has had a few cases of burnt clutches) and i dont even bother rev matching when im at low speeds (like stopping at a traffic light or in housing areas etc) and my bike has been fine.

just enjoy riding the bike and downshift like normal. again, no need to overcomplicate things.

Pijak only.... is called "zam" gear

if after u pijak, and u let go quickly, the bike will jerk forward and engine will roar
if after u pijak, and u let go slowly, the bike will jerk less and slow down as engine rev goes up

if after u pijak, u play play throttle, then let go, none of the above will happen, and then continue to ride

be one with the bike

Yes thats the normal. Thats the way almost everyone downshifts
All vehicles will jerk when downshift without rev matching correctly