Step 2: Define rules

Name: Choose a name on your own for the Filter. For example: Forwarding without local copy

For an incoming message on the following is true: Select Any.

the following conditions: Set the conditions together, to take place while the transfer.
Select To / contains / alias@domain.tld

Enter instead alias@domain.tld your address with which you are logged in, so routing can take place without a local copy of this account.

Click on Add action.

Select Redirect to / test@domain.tld

Enter instead test@domain.tld the address to which the e-mails are forwarded.

Before saving, select the check box Process subsequent rules even when this rule matches.

Click on Save to save your Rule.

It will now appear in the menu on the left.