Time management puts goals and plans into a timeline. Once a goal is broken down into component parts or steps, a schedule defines when those steps will be done or when the component parts will be completed and ready for use.
If only one goal exists at a time then scheduling the necessary work is a fairly straightforward process of figuring out how much time each step or component will require. However, most people have multiple concurrent goals and activities to manage at any point in time. Students have multiple classes, each with their own assignments. Teachers have past homework to review, assessments to write, and future lessons to plan. Parents have work, home, childcare, and personal interests to pursue.
The time management challenge is to fit all of these competing priorities into one balanced schedule that accomplishes what we plan without too much stress.