You have 3 options to import you wallet in the web version:

1. With you 12-word mnemonic phrase.

Click on "import wallet" on the main page, pick Option 1 and enter your mnemonic.

2. With a wallet file.

Click on "import wallet" on the main page, pick Option 2, upload your wallet file and enter your wallet password.

3. With a private key.

Click on "import wallet" on the main page, pick Option 3 and enter your private key.