Define the activities, set dependencies and estimate durations
Sequence the activities (tasks) by defining their predecessor-succesor relationships (links).
To create links, move the mouse over the predecessor bar in Gantt Chart until the cursor

appear and drag to the succesor bar or select the tasks and click the

icon.
The default link type is
Finish-to-Start.
To change the type, select the linked tasks and activate the details window (click

icon), or double-click the link arrow in the chart.
Now you can also set the link's lag, that means the duration between the specified dates of the predecessor and succesor.
For
Finish-to-Start, lag time is the delay between the predecessor's
Finish,
and the successor's
Start. A negative lag is equivalent with a positive lead time.
A constraint to a task can be set by selecting its type and date in the
Details tab in details window (

).
Attention: moving a task bar in the Gantt graph by dragging it with the mouse cursor will set a start-no-earlier-than (SNET) constraint on the task!
Estimate each activity duration and set it in the duration column.
Some tasks could require different calendars from the project one (e.g.: an activity that cannot be interrupted should have a 24-hours calendar, but the others follow a standard 8-hours calendar).
Assign calendars to tasks by clicking in the corresponding cell from
Calendar column and selecting the right one.
If it's necessary, define additional calendars at the
Calendar step in the Guide with the
New command, or in the
Settings menu,
Calendar.
Resources use task calendar checkbox in the
Details tab will force the assigned resources to work following the calendar set for the task (project or specified calendar) even though it could mean to work overtime.
Edit notes to remember important details related to tasks.
Hint: you may personalize Gantt table by adding or deleting columns. Click on the button in the upper-right corner of the table and mark only the columns you need.