[task1] starts the 1/1/2018[task2] starts on the 1/1/2018
[task1] starts the 1/1/2018
[task2] starts on the 1/1/2018
But it seems that tasks can only start on the beginning of the diagram and then we can only queue tasks when others end.
It would be nice if they could start at arbitrary dates.
You can use
Project starts the 20th of september 2018
[task1] starts on the 2018/9/1 and lasts 10 days