Look at Tools>Message Filters. From there, you can select the account, the condition on which emails to forward and the recipient of the email.

Consider setting up the account to which mail is forwarded to collect mail from the account that receives new mail. For example, in gmail webmail Settings, Accounts & Import, there is an option 'Check mail from other accounts'. Other providers have a similar option. This has the advantage of working when TB is not running.