not understanding experience

it seems like there's something missing from our understanding. it's hard to say what exactly.

but, the main annoyances are...
(1) when i say "nature appears to be calculating" such and such, i really don't know how nature does what it does to calculate things.
(2) if nature needs to keeps track of multiple states of a person, i'm not sure if they are all "turned on" - like i don't know if they are all experiencing reality like i am

if i run a simulation of a human on a computer, is it experiencing something?

what if instead of running the simulation on a computer, i just do it on paper - you can do that - anything a computer can compute can be done on paper - it just takes longer and is really boring.

but if i'm doing that on paper - is the human i'm simulating experiencing something?