Wallet Setup
Install the polkadot.js extension
Section titled “Install the polkadot.js extension”You can get the polkadot.js browser extension from here:
Import the key
Section titled “Import the key”Import your mnemonic as a key into the polkadot.js extension.
First, open the extension. Then, press on the button at the menu:

Press on “Import accounts from pre-existing seed”, then follow the dialog to import the key.

In the end, you should see the address corresponding to your validator key. Use this address when getting the tokens from the faucet.