well you can either learn using C/C++ ... which it is relatively simple to make them like most C based programs
start with including your headers for what your going to use...
lets just say the standard stuff like
#include <windows.h>
#include <stdio.h>
i know you don't need all of them its just what i standardly add

then define a command export lets say ... now any function you use this definition of you'll be allowed to export the results.
#define FluxCommand __declspec ( dllexport )
you then setup the function in C like,
FluxCommand void MyCommand()
{
MessageBox( NULL, "Something", "Uninteresting Title", MB_OK)
}
right now you compile as a Direct Link Library, Borland no doubt has a standard setup - i remember in 5.5 i spent a good day figuring out the setup then i'd AutoDLL.bat just change a line to where i had to compile
now search through the DLL with notepad or something for MyCommand and you'll find it with something afterwards probably MyCommand%XYZY or something like that (i know theres a partern between the callname and the functions import/export but i've not learnt it yet

)
you now load the DLL like
Load DLL "Flux.DLL",1
copy that to somewhere you'll remember it because that is the call name within your program ...
you then do Call DLL 1,"MyCommand%XYZY"
and finally use it in the program
sync on
load DLL "Flux.DLL",1
while scancode() = 0
call DLL 1,"MyCommand%XYZY"
endwhile
and your message box will popup with your string in

useless but cool
Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?