1. Log in to your Orangescrum account using your current credentials.
2. Navigate to Left Menu >More > Gantt Chart
3. Select Project, Click  icon (from respective Task Group/Sprint), provide required details & Click Save (Refer Image 1 & 2)

(Image 1)

(Image 2)

Note: Whenever you are making any changes to Gantt Chart, don’t forget to click on on the Gantt Chart.