> For the complete documentation index, see [llms.txt](https://docs.enzyme.finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.enzyme.finance/enzyme-blue-sdk/building-blocks/class-instantiation.md).

# Class Instantiation

Instantiating a Contract Class requires two steps. First,  import the Contract you need from the SDK. Imports are explicit; read through the protocol architecture [docs](https://docs.enzyme.finance) or the [repo](https://github.com/enzymefinance/protocol) to understand which contract (or contracts) you will need.

```typescript
import { ComptrollerLib } from '@enzymefinance/protocol'
```

Next, instantiate a new class by passing it two parameters:

1. The `address` at which the contract is located on chain. Vault-specific contract addresses are available on the Vault's overview page on the [Enzyme app](https://app.enzyme.finance). Non vault-specific contract addresses can be found [here](https://contracts.enzyme.finance).
2. A `Signer` object. A Signer is a class imported from `ethers` and instantiated per their documentation. It describes the user on whose behalf the contract is being instantiated (and who will eventually call any methods on the class) and a connection to an Ethereum node.

Ethers [provides a good description](https://docs.ethers.io/v5/api/signer/) of the `Signer` object, and it's beyond the scope of this document to go into more detail. You can see an example of how a signer object is instantiated and passed to an Enzyme class in practice in the example [Enzyme Bot repo](https://github.com/avantgardefinance/enzyme-bot) and [accompanying blog post](https://medium.com/enzymefinance/building-a-trading-bot-on-enzyme-e002b6419b23).

```typescript
const address = '0xw23r...' // for example only
const signer = new Signer(privateKey, ethNodeAddress) // for example only

const vaultComptroller = new ComptrollerLib(address, signer)
```


---

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