Very good, All you need is patience, Keep on changing with the replay to have a good result.
Simply use "E" while the replay is playing, Then you will enter "Edit" mode.
Just don't give up :P...
Also, To train yourself, You MUST understand how joints work,
To do so, Spend an hour or two moving joints and looking at how it affects the ghost.
Hope you become a master someday,
~bshark