Problems with installation process of worxlandroid .jar file

Hello together, I'm very interested in this package to integrate the worxlandroid-mower in the OH-World. It seems to be a very nice solution. I use openhab for several home-automation-functions-but I'm an absolute beginner... So-I have a problem with the installation-process of this package. After copying the actual ".jar"-file in the addons-folder of my Openhab-Installation it doesn't appear in the PaperUI (configurations=things...plus). Also the manual installation-procedure didn't work. Any idea how this could be?

I use Openhab on a RaspberryPI3 B+.
My Openhab-Version is 2.4.0

Thanks in advance

nibi79 / worxlandroid

Problems with installation process of worxlandroid .jar file #16