how to recompile a linuxcnc directory?

Hello my friends, I made some changes to create some pins in the halui.cc file that I acquired on github, but I have no idea how to recompile it so that the changes are children, could anyone help me? Maybe give a step-by-step guide on how I can recompile. thank you in advance

and there is no way to just compile this file? just building Linuxcnc from scratch? I'm not very experienced with this, I thought maybe it wouldn't even compile a component, but apparently it's more complicated than I imagined it would be.

The build system should just build what you have changed.

I'm going to study the manual, but I've never done it, I'll probably have several questions as I go along, I ask you to be patient with me, but I thank you for taking the time to answer

There are rules in files named 'Makefile'. You can consider to learn how make works. To compile only halui, just do these steps below:

1. Go to your project directory
2. Go to src directory located in your porject root directory
3. run this: make ../bin/halui

You can compile only halui.cc with these steps. But before doing it, be sure you already configured the source tree.

halui executable is being outputted at bin directory in your project root directory. This is why you are should run ../bin/halui rule in Makefile located in your src directory. You can build many single executables with this combination. If you wanna learn what does the Makefile include, just do these:
1. type this to your shell in src directory: make 
2. After typing 'make', press space to give space character
3. Press TAB two times. 

It is gonna show the rules. You can build axis, mdi, milltask, halui, iocontrol etc. in the same way.