data layout for charts

Please HELP, Hello I'm very new to Excel (as in two weeks) I'm a quick learner and have done well with some decent formulas but I cant this simple date to sort the way I want. I've been using PT and they are been fairly great for the most part(outside of the learning curve).

What I got for data is a long list of projects(one unique # for each) that have one main event day(date, some times share dates)) associated with it, and then several modifications that that happen before, on and after the project date. With each modification there is a associates name too.

For starters I cant seem to get the data to layout right to even graph it (view several timelines on one virtual timeline), but its hard since there is a "floating" main day for each study. The list is very long (thousands) so I don't want to have a chart that is miles long either, suggestions????
See attachment for visual.

I've been staring at this for days and this one issues I can seem to manage.

Thank for time in looking at this!