The addon automatically adds a farmer job to your server.
If you have a farmer job on your server then I recommend deleting that team as it might cause conflicts.
If you wish to edit the farmer job that comes with the addon, then you can find it in ch_farming/lua/ch_farming/shared/ch_farming_darkpadds.lua on line 4.
You can edit the teams that can speak to the NPC in the config file at ch_farming/lua/ch_farming/shared/ch_farming_config.lua. Edit table CH_Farming.Config.FarmingTeams