You have 2 options to import your wallet in the web version:

1. With your 12-word mnemonic phrase.

Click on "Import your existing wallet" on the main page, pick Enter mnemonic tab and enter your mnemonic.

2. With a wallet file.

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