LVGL has nothing to do with PROS. It is a third-party graphics library, that functions on any type of hardware. It is a minimalist C library that is completely self-contained and can run on most processors with a display.
You can run the same LVGL code on any platform, whether it be the V5, your PC, or a rasberry pi.
All the simulator does is compile the LVGL C code to run on your computer, so you can test it.
You can develop your display codes in the simulator, but then copy them over to PROS, but it is completely separate from PROS except that they both support LVGL commands.
The guide I linked to has all the information on how to set it up with various IDEs.
make is an industry-standard tool used to automate the compiler. It uses information from a
Makefile to know how to use the compiler to compile an entire project.
The LVGL simulator comes with such a Makefile, which is easier to use than eclipse. However, following the VSCode guide might be easier, I have not tried it.
PROS has already installed
make for you, as it uses it for its own compiling.
Just read the guides if you have more questions, the demo projects contain all the necessary drivers.