3. Attester signs up

Create an attester's wallet

const attester = new ethers.Wallet(
    ATTESTER_PRIVATE_KEY,
    provider
)

Attester signs up in UniRep smart contract

const tx = await contract
    .connect(attester)
    .attesterSignUp()

Then the attester can get his own attester ID

const attesterID = await contract.attesters(attester.address)
console.log(attesterID)