For anything but very small projects, you will need a tool to record and track your schedule. The most common tools used for this are Microsoft Project and Excel. They are not the only ones available but they are the ones I will discuss here.
Microsoft Project is a very robust scheduling tool with many features. You enter tasks and sub-tasks, assign resources (you can do this with varying percentages of availability), identify the effort needed for this task (in days or hours), and link the task to dependent tasks. The software automatically creates a schedule from this information.
Often on the first cut at creating a schedule, the project end date is beyond the desired target date. The sequence of tasks that directly connects to this end date is called the “Critical Path”. It is the longest path of dependent tasks in the project. This path of tasks are your top priority to monitor because slippage in any one of these tasks will increase the length of your project.
You must look for opportunities to bring the target date in line with expectations. You can do things like add more resources, bring in more skilled resources, look for opportunities to do tasks in parallel, and/or start some tasks earlier. Be mindful of budget, risk ad quality implications when you use these techniques.
Excel can be used for small and some medium sized projects where you just need a list of key activities and the start and end dates. Unlike MS Project, Excel cannot create the schedule for you. It is used strictly for tracking and communication. It is much more convenient than Project when you don’t need all of the scheduling features.
I advise you not to create a schedule with so many tasks that it eats up your valuable project management time just maintaining the schedule. Create the schedule at a level sufficient enough to track the Critical Path and communicate status to key stakeholders. Keep in mind your Project Plan has all the activity details so there is no need to duplicate all of that information in the schedule.