NefMoto

I have posted before trying to unearth more information on the subject but I think I need to take a step back even farther.

So I guess my next question to those who regularly dabble within IDA pro and assemble their own functions would be, where can I learn more about it? What assembly language are these functions written in?

I need to pinpoint where would be best for me to start reading into to make the information I have collected and somewhat comprehended make a little more sense.

TIA

They are usually a mix of code generated C from ETAS Ascet or similar, human written C and a sprinkling of assembler.

There is no shortcut to thousands, and usually tens of thousands of hours in related fields to get good at it.

It is way better to write in C, but you need to master assembly first in this case because your are patching something already compiled.

Correct, its the same as you cant learn a language in 2 days.
Rudimentary takes you a few weeks or months, mastery of that language can take you years and more.

Cmon it's just an asm
Take that move to this, compare etc
A weekend deal

Just take an c167 instructions manual and disassembled flash
And see how things done

Maybe for someone who has knowledge of the fundamentals,
if you dont know hex, understand how a cpu is supposed to work, what interrupts are and how on earth special registers work it might be a lot harder.
Whats an eeprom, how is it interfaced, how does a flash work (how does one enable writemode on flashes etc etc). Why are most digital inputs configured as LOW = true and so on and on and on.

But well, in the end it all depends on how deep you want to dig.

Do you have any example, a file with disassembled flash.  Does that file load to IDA?    I have all that in "air"  and have concept about it. 
Let's say this page, i undestand all how to do, but not how to use IDA, how to load this files. And can I use IDA demo?

https://www.drive2.ru/l/534054239161286663/

None of this is even remotely translatable to you unless you have at least some background on how a CPU works.

Test me...
As I said, I have all that thing in 'air' I can take a data sheet and read it for months. But if I have a living exemple like from this link. It can shorten my time for learning that a really much.
That is a learning curve like in school, first you have teory, than some simple exemple. And after that you are by your own for some complex task

IDA demo doesen't alow me to open that first file from link

IDA demo does not support other CPUs than x86 x64 iirc.