A task duration can be set in the following ways:
Drag the left or right end of the task using mouse, and release when done.
Double click the task bar or task in leftside grid. This will open task edit dialog. Set desired duration and click Save.
Supported duration units are:
d for days
h for hours
m for minutes
The order of units is not important. So you can type 3d 2h 25m, or 2h 25m 2d
Any unit can be skipped. Example: 2d 15m, or just 3d
Unit values above the limit will be auto-corrected by the app. For instance, if you type 600m, it would be converted to 1d 2h (because 600m equals 10hrs).