In the Durations and Rates tab you will see 2 Sections;
Durations, includes create-button and a list of the durations on the Time Charter Contract.
Duration and Rates, includes a list of the Rates along with the connected Duration on the Time Charter Contract.
When adding, removing or otherwise changing the durations on a Time Charter Out, and the Voyage has status Estimate, the redelivery date on the contract is automatically updated.
In the Durations Section you create new durations by clicking the -icon in the top right of the Section and click on any of the durations to edit or delete them.