chess boar installation

hi,
i would like to install an applet, actually a chess board.
i dont know how to correct the general instruction that i got, to make it work.
the instruction are available https://www.bennedik.de/Silverboard.html

the main problem i think is to identify this applet as an application and to define the correct url where to find the source.

i’ll thank you very much for any suggestion

Joe