Download Artoolkit and extract it to a specific folder.
To create your own markers, you have to start with a blank rectangle located in doc/patterns/Blank pattern.png.
Change the Blank pattern image by inserting some pattern in the middle of the rectangle. I have modified the image to this image shown below
Go to bin folder of recently downloaded Artoolkit library and click on mk_patt.exe file. It would ask you to enter "Camera parameter filename", just press Enter
This would start your camera on PC. Point your camera towards the image you created in step 3
You should be able to see a red and green square around the Marker. After you see the red and green line besides your marker it means that the ARToolKit has found the marker. The red corner should be at top left corner of your marker only. After marker detection just press Enter.
You would be promted with "Enter your pattern name". write the pattern name in this format "patt.filename" ex. "patt.kanji" Then press Enter
This would create a pattern file named "patt.kanji" in bin folder. Move this file into Assets/ARToolKit5-Unity/Resources/ardata/markers folder. The pattern files are accessed in this directory
You have successfully created your marker. You can now use that marker in your application
If you have any doubt or suggestion, please comment below. That would help you as well as others who read this post.