Computer Diagrams

How do I calculate a project schedule using a network diagram?

I am stuck on learning how to calculate a project's schedule using a network diagram, when given each task's number, duration (in weeks) and it's predecessor/s. From this I need to calculate times for "early start", "late start", "early finish" and "late finish", as well as the "slack" and "critical path". I have tried googling for an explanation but I keep getting confused. Does anyone have a simple, easy to understand method of working it out?

Public Comments

1. First you need to determine the "critical path". This can be determined by mapping from the first activity, using predecessors, to the last. The shortest path is called the critical path. Activities along the critical path will have the same values for early start, late start, early finish and late finish. Activites not on the critical path will have slack, meaning that these could start or end without impacting the critical path. Slack is the value of the difference betwee early start and late start.