Classes and .ino files

Hello

I have seen several Github folders and there are many projects, like B-Robot, that post multiple .ino files. My question is, does arduino run multiple .ino files in parallel (simultaneously) or do I have to compile the entire algorithm on one .ino file...

If it does, how do you associate the separate .ino files into the same application and how do you do that from the arduino IDE?

If you need a variable that's generated from one .ino file, how do you access in another .ino file. I have programmed object oriented before using C# and Unity. The way to access variables from another file was to declare global and create an instance inside the file that's trying to access the other class's functions or variables. Does arduino sketch allow for this type of access and how to combine files into the same project?

I need to use MPU-6050 data to control DC motor direction and speed but the MPU code in the ino file is disrupting the speed control. So I figured maybe I need to de-couple the two processes.

Thank you.

There can only be one ino file. The rest are header or cap files.

You can only run one process so any multitasking that happens has to be in your code.

Normal c++ scope and grammar rules apply for Arduino code.