Reading the ranks of the rival playing several tables

Hi everyone.

I am studying a lot and watching a lot of videos lately to try to improve my game, beyond that for now I don't see good results.
Something that strikes me and probably has to do with being a novice (I hate the words fish or recreational player because it sounds like someone who is not trying to improve and is not my case).
Something that I see a lot in the videos is reading the rival's ranks, something that seems fundamental to someday being a winning player.
But there is something that my princely head asks: how can you read the ranks of an opponent playing eight tables at the same time?
I am one of those who believe that by playing many tables one plays only with their cards, but I would like to know how they read ranges in this instance "those who know and win".
I still don't use any HUD since I don't have the money to buy it and it may be too early to use that kind of software.
Any advice or opinion from you will be very welcome.

Thanks in advance.

Kind regards from Buenos Aires.


PS: I don't play cash, I play mtt and sits.

how read the ranks? what is it? or is, how read the hands (ranges...)?
hard question, but i believe some guy with experience in multi tables, will show a answer, because I barely can play 4 tables at same time, so I can't help