Use Ethers.js to interact with a deployed smart contract

I use Ethers.js to interact with a smart contract that deployed on the Kovan testnet.
You will need a) the smart contract address and b) the ABI.
I use an Ethers provider to perform read transactions.
I use an Ethers signer to perform write transactions.
Ethers documentation:
docs.ethers.io...
docs.ethers.io...
docs.ethers.io...
Github code:
github.com/rob...