STEP 1 => Deployed the Token contracts for TokenA and TokenB and copied its address to deploy the SimpleDEX contract.
Deploying SimpleDEX.sol with Contract address of TokenA and TokenB with exchange rate 5.
Approving and transferring the tokens to SimpleDEX contract.
Interacting with SimpleDEX.sol and intiating exchangeTokenAForTokenB function with 500 amount of token.
Verifying the updated balance of TokenA and TokenB , Here TokenA has 10500 after exchange TokenB has 7500 after exchange as exchange rate was 5 hence 5*500 = 2500 deducted. Updated Balances can be verified under balanceOf function of both tokens.