Hi . How do we add items to the Blacklist? I try everything nothing works. Can you help me thanks

From the plugin page:

• blocker [term] -- Blocks item, entity, construction grade or asset path.

 [term] would be replaced with the item name or other type mentioned above.

This is what I used and it worked.

{
"blockList": ["snowball"],
"craftRefund": true,
"messages": {
"You are not allowed to use this command": "You are not allowed to use this command",
"You may not craft this (restricted)": "You may not craft this (restricted)",
"You may not deploy this (restricted)": "You may not deploy this (restricted)",
"You may not pick that up (restricted)": "You may not pick that up (restricted)",
"You may not research this (restricted)": "You may not research this (restricted)",
"You may not research this (restricted), blueprints refunded!": "You may not research this (restricted), blueprints refunded!"
},
"VERSION": "0.1.3"