🚀 go-pugleaf

I am writing a comms software program for my University course and
am after a program/utility that may assist me in planning/outlining
the tasks and the order of those tasks needed to complete my project.

For example if I have listed certain steps I need to take to reach
a goal in my first draft and subsequently find other steps that need
to be inserted I want to be able to do this. I could of course write
and re-write all this out on paper but I want also take into account
time estimates. 

Maybe I need a simple project management type application but I have
never seen one to know if they are suitable.

If you are not thoroughly confused by this request (reading back I think
I may be) perhaps you can help me.

any replies appreciated
thanks
dazz

ps. it needs to be free or cheap, I don't see much use for such a 
    thing after I complete my project.