Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.8.3+commit.8d00100c.js&optimize=true&runs=200&gist=

bank.sol

pragma solidity ^0.8.0;

import "https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-contracts/master/contracts/token/ERC20/ERC20.sol";

contract TST is ERC20 {
    constructor() ERC20("Test token", "TST") {
        _mint(msg.sender, 10000 * (10**uint256(decimals())));
    }
}

contract Bank {
    // deposit ETH function
    
    // withdraw ETH function
    
    // deposit token function
    
    // withdraw token function
}

contract Setup {
    ERC20 public token;
    Bank public bank;
    
    constructor() {
        token = new TST();
        bank = new Bank();
    }
}