In this exercise, we learnt

1. how to initialize provider - new ethers.providers.jsonRpcProvider(<alchemy url>)

2. once we have provider, we can get wallet balance of any address
   const balance = await provider.getBalance(<address>)

3. you can get block number
   const blockNumber = await provider.getBlockNumber()

4. Signer is an abstraction of a account object - and helps us to sign txns
   In our case, we use another object that inherits from signer - wallet

const wallet = new ethers.Wallet(<PRIVATE KEY>, <provider object>)

This will create a wallet object that is connected to provider

5. We can get wallet address and wallet balance
   const balance = await wallet.getBalance()

const address = await wallet.getAddress()

6. Once we have balance and address, we can sign a txn using wallet
   const tx = await wallet.signMessage("Hello World")

7. We can transfer funds to another account
   const tx = {to: <address>, value: ethers.utils.parseEther("0.01)}

const transferTx = await wallet.sendTransaction(tx)
const txReceipt = await transferTx.wait(1) // waits 1 block

8. Abbove showed how we can connect to a ethereum node implementation (Geth/parity or infrastructure provider infura/alchemy) - via JSON-RPC-API.

9. We can do the same to connect a front end application to node - assuming front end application is running on Metamasl

const provider = new ethers.providers.Web3Provider(window.ethereum)

window.ethereum is an objected injected into browser by metamask - this in essence is the JSON RPC Provider - Metamask helps in both connecting to a node and signing a txn

// once above is done, get signer
const signer = provider.getSigner()