[Ethereum] the best way to handle multiple NFTs of the same collection in ERC1155

I'm learning ERC1155, and I'm a bit confused.

This is OpenZeppelin's example of an ERC1155 Contract:

They state that Thor's Hammer is an NFT (because only 1 was minted), while Gold is Fungible.

Therefore this example contains several Fungible Tokens:

• Gold
• Silver
• Sword
• Shield

And only one Non-Fungible Token:

• Thor's Hammer

But what if I want my ERC1155 contract to have multiple Collections of Non-Fungible Tokens?

For example, say I want to create a Football Game with:

• 2 types of Fungible Tokens:
  • Gold
  • Silver
• 4 Collections of NFTs:
  • Players
  • Coaches
  • Jerseys
  • Stadiums

Example code:

//SPDX-License-Identifier: UNLICENSED
pragma solidity 0.7.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/solc-0.7/contracts/token/ERC1155/ERC1155.sol";

contract FootballGame is ERC1155 {
    
    address public admin;
    
    // Non-Fungibles
    uint8 public constant PLAYER = 1;
    uint8 public constant COACH = 2;
    uint8 public constant JERSEY = 3;
    uint8 public constant STADIUM = 4;
    
    // Fungibles
    uint8 public constant GOLD = 5;
    uint8 public constant SILVER = 6;
    
    constructor() ERC1155("https://example.json") {
        admin = msg.sender;
    }
    
    modifier onlyAdmin() {
        require(msg.sender == admin, "This operation is only for Admins");
        _;
    }
    
    function mintCoins(uint _coinId, uint _amount) onlyAdmin external {
        require(_coinId == GOLD || _coinId == SILVER, "Invalid Coin ID");
        _mint(msg.sender, _coinId, _amount, "");
    }
    
    function mintNFT(uint _tokenId) onlyAdmin external {
        require(_tokenId == PLAYER || _tokenId == COACH || _tokenId == JERSEY || _tokenId == STADIUM, "Invalid Token ID");
        _mint(msg.sender, _tokenId, 1, "");
    }
}

Is this right?

The constant variables are supposed to be IDs that represent each type of token, right? Or wrong?

For instance, if I want to create multiple Stadiums can I just mint multiple NFTs with the ID of the Stadium collection?

Or do I have to mint Stadium A with ID 22, Stadium B with ID 23, Stadium C with ID 24, and so on?

For NFTs in ERC1155, is an ID for each NFT? Or is it for each Collection of NFTs?