Scheduling is about deciding the time that each task will take to do and the sequence in which the tasks will be carried out. There are a number of approaches to estimating the time and effort (and, therefore, cost) required to complete a project. Some estimates may be based on past experience but, because each project is essentially unique, this alone may not be sufficient. A clearer picture can be obtained by measuring each task in terms of the content of the work, the effort required to carry it out, and its duration. This should enable you to estimate resource requirements in order to begin scheduling, taking account of the current workloads of the members of the project team and their capacity to carry out the work.
Usually there are some things that must be completed before others can be carried out. This is called dependency. When one task is dependent on another, the sequence needs to be planned, but there is also the possibility of delay if the dependent task cannot be started until the previous task is completed. The Gantt chart and critical path analyis are two useful techniques that will help you to plan for each of these issues.
The Gantt chart enables you to establish the sequence of tasks and subtasks and to estimate a timescale for each task. It will allow you to block out periods of time throughout the duration of the project to ensure that it is completed on time. The Gantt chart is not so useful in demonstrating the dependencies and the impact of delay if any of the foundation tasks are not completed as scheduled. A technique called Critical Path Analysis (CPA) is frequently used to plan the implications of dependencies. We shall look at each in turn.