Viem represents connected wallets as a wallet client object, which you can use to get information about the current wallet or the request signatures and transactions. To get a viem wallet client for a user’s connected wallet, first import your desired network from the viem/chains package and import the createWalletClient method and custom transport from viem: 
import {createWalletClient, custom} from 'viem';
// Replace `sepolia` with your desired network
import {sepolia} from 'viem/chains';
Then, find your desired wallet from the wallets array and switch its network to the chain you imported, using the wallet’s switchChain method: 
const {wallets} = useWallets();
const wallet = wallets[0]; // Replace this with your desired wallet
await wallet.switchChain(sepolia.id);
Lastly, get the wallet’s EIP1193 provider using the wallet’s getEthereumProvider method and pass it to viem’s createWalletClient method like so: 
const provider = await wallet.getEthereumProvider();
const walletClient = createWalletClient({
    account: wallet.address as Hex,
    chain: sepolia,
    transport: custom(provider),
});
You can then use the wallet client to get information about the wallet or request signatures and transactions.