I spend 3 hours reading the documentation and messing with the settings, I still can't figure out how to add storage to my transport helicopters.

  "ScrapTransportHelicopter": {
    "DefaultProfile": {
      "AdditionalStorage": {
		  "LeftBox": 48,
		  "RightBox": 48
    },

Is this correct?
In the documentation, its not clear what value should I put in the "DefaultProfile". Is it a number? or box name?
I dont know any coding, what's those { are for? should I remove it?
Your documentation really is confusing, can you please at least do an example on how to configure the settings? Like how to put a storage on a minicopter behind the fuel tank? The preset is in the json but how do I enable it?

The ScrapTransportHelicopter example looks right, but probably missing a closing }.

I've updated the docs with the an example similar to the following for Minicopter. Note that I'm using "..." below as just an abbreviation to show the structure.

"Minicopter": {
  "DefaultProfile": {
    "AdditionalStorage": {
      "Stash Below Front Seat": 48
      "Stash Below Pilot Seat": 48,
      "Box Below Fuel Tank": 48,
    }
  },
  "ProfilesRequiringPermission": [
    { ... },
    { ... },
    { ... }
  ],
  "ContainerPresets": {
    "Stash Below Pilot Seat": {
      "Prefab": "...",
      "Position": { ... },
      "RotationAngles": { ... }
    },
    "Stash Below Front Seat": {
      "Prefab": "...",
      "Position": { ... },
      "RotationAngles": { ... }
    },
    "Box Below Fuel Tank": {
      "Prefab": "...",
      "Position": { ... },
      "RotationAngles": { ... }
    }
  }
},

How JSON syntax works by example

{ 
  "Number Example": 123,
  "Boolean Example": true,
  "String Example": "alice",
  "Object Example": {
    "Number Example": 123,
    "Boolean Example": true,
    "String Example": "alice",
  },
  "Number Array Example": [ 1, 2, 3 ],
  "Boolean Array Example": [ true, false ],
  "String Array Example": [ "alice", "bob" ],
  "Object Array Example": [
    {
      "Number Example": 123,
      "Boolean Example": true,
      "String Example": "alice",
    },
    {
      "Number Example": 456,
      "Boolean Example": false,
      "String Example": "bob",
    }
  ]
}

Thanks, I think I did deleted one } by mistake, the server keeps throwing out error everytime i reload the plugin even after I deleted the storage lines.

So, anything below "ContainerPresets" is just a setting of where that storages position is (I think I should never mess with that), and anything below "ProfilesRequiringPermission" is the same setting as "DefaultProfile" but only for vehicles that uses permissions, and I should never touch that since I'm not using any of those permissions/locks/key, am I right?

To get storages in a vehicle (without using permissions), I just copy the box lines (of any box type that I want) from here

 "ProfilesRequiringPermission": [
      {
        "PermissionSuffix": "2boxes",
        "AdditionalStorage": {
          "Front Left Box": 48,
          "Front Right Box": 48

and put it under "AdditionalStorage": here after {

 "Chinook": {
    "DefaultProfile": {
      "AdditionalStorage": {}

and close it with } just like your example. I can change the slot number to anything that I want, right? Is there any limit?

So, I'm on a right track now, but how about if I wanted to add more slots to a Storage Vehicle Module of a modular car for example?

Yes, that's right.

Max capacity is 48. Vanilla cannot display any more slots than that. If you configure higher, the plugin will automatically limit to 48 and print a warning to let you know.

To configure vehicle module storage, update BuiltInStorageCapacity, which is part of the profile, next to AdditionalStorage. That option is already present by default for all vehicles that have built in storage containers.

I got it working now, Thanks for the explaination!