Korean Station Set is a NewGRF that adds several korean style station pieces into OpenTTD.
You can download this via Online content in-game, or Github release page.
You need M4, grfcodec, nforenum, appropriate m4nfo modules and m4nfo NewGRF linker to build this NewGRF.
Please check the m4nfo manual to download these software.
Then put m4nfo module m4nfo_objects.m4 and m4nfo_stations.m4 and count32.m4 into project folder and run make in command prompt.
make bundle will create tar files which can be uploded to BaNaNaS.
make clean will clean all generated & compiled files.