https://github.com/paritytech/xcm-format
represent the pallet index in Runtime construct_runtime!
For example: palletInstance=3 represents the Balances pallet
<chain>/PalletInstance(<id>) for a Frame chain with a single-asset pallet instance (such as an instance of the Balances pallet).
<chain>/PalletInstance(<id>)/GeneralIndex(<index>) for a Frame chain with an indexed multi-asset pallet instance (such as an instance of the Assets pallet).