Open Remix and select the source file
Open remix.ethereum.org.
In the file explorer, select the source code file that was originally used to compile the deployed contract.
Compile the contract
Open the Solidity Compiler section.
Select the correct compiler version for the source file and start the compilation.
Resolve any compiler errors before continuing.
Open Deploy and Run Transactions
Open the Deploy and Run Transactions section.
Expand the environment selector and choose Browser Extension.
Connect the wallet
Select the wallet connection option and choose Rabby Wallet or another compatible browser wallet.
Confirm the connection request and verify the selected account and network.
Open the contract selector
In the deployment panel, expand the contract dropdown.
The list contains contracts successfully produced by the current compilation.
Select the compiled contract
Find and select the contract that matches the already deployed address.
Make sure you choose the final token contract rather than an imported interface or library.
Choose Add Contract
Locate the Deployed Contracts area.
Select Add Contract to attach an existing deployment to the current Remix workspace.
Enter the deployed address
Paste the existing deployed contract address into the field.
Verify that the address belongs to the currently selected network.
Select Add to attach the contract interface.
Verify the restored interface
The contract should now appear under Deployed Contracts.
Expand it and verify that the expected read and write functions are visible.
Before submitting any transaction, check the connected account, network, contract address and function parameters.