1) If the scope has only been defined at a high level then the next step would be to fully define the scope with a product and work breakdown structure. The PBS would define all the deliverables that the project has to produce, in a structured way. The WBS would define all the work required to produce those products. For examples a new house would have foundations, wall and roof. The Work would be laying the foundations, building the walls. By checking these deliverable sheet stakeholder expectations we can be confident in the scope.
2) The next stage is to develop a precedence diagram. This shows the dependencies between the deferring activities. To make sure it is robust we would need to review it with the technical leads. This would check that the dependencies follow the actual path for the work.
3) The next step is the accurately estimate the durations and enter these into the dependency network. This can be difficult if the work is novel or you are unsure how many resources are available. It is easier if you have done this type of work before. There we can use comparative, parametric or bottom-up techniques to estimate the duration of each activity. The more data we have, the better the estimate will be.
4) Once we have the duration, we can develop the critical path for the project. This will inevitably need to be optimised and review to make sure that it is realistic and robust. We can do this by comparing to similar projects or by peer review. Often measures may be needed to accelerate the deadline such as increased parallel working or increased resources.
5) The final step is the resource load the project and then optimise the resource demand vs availability. Here we can use resource levelling or smooth to get a realistic and achievable schedule. To make if robust we should make realistic assumptions about resource availability. We can also allow some contingency resources in case any risks occur during the project.