Monday Hour One question

Time Management is going to be game-changing in my life because I have so much to learn!  Let’s say I have a list of tasks to complete from 2-3 p.m.  I don’t do them.  New task comes up for 3 p.m.  Do I do the 2 p.m. tasks and move the whole schedule down an hour?  Or move the 2 p.m. tasks to another day/time, or next week so I can stick to the 3 p.m. plan?