Does anybody know where I can go to get a good tutorial for these type of questions. I have sat the exam twice now and I am having continous problems with these questions.  I don;t know whether I should draw the PDM using EF,ES,LS,LF diagrams and then work out the solution. Some questions just show a box with a and then a line with a duration on it asking you to give lead and lag times.

I am totally confused and need real help with this section.

Any ideas appreciated!!