Plugin problem ;( ;(

I selected: Plugins and searched Cursed Minecraft Plugin (by Dream) and I selected this I installed problem is because plugin dont work I typing /cursed and unknown command type help and problem is I have gCursed.jar (I think this file is for cursed mc plugin) and I have spigot 1.12.2, plugin dont work

And I dont have plugin on /pl list

everything I've tried:

-Stop server and install

-Few restart servers after install

-unlog all players and install and restart

-Install two versions at the same time

all the attempts above did not help

But how logs?

i must create gCursed fodler and share gcursed.yml?

Ah okay my server logsokay I know but how can i do this?

Okay I solved problem,my server logs says i must i9nstall protocollib remove thread