Help needed editing this chart template,help me keep my job please

[MasterPM]

Good afternoon to everyone reading my post , i appreciate the time you are taking in it
this is the case, my boss expect much from me in my new job..
its a contruction project, we are the warehouse deparment..
the idea here is create a timeline in excel to demostreate by the mean of a presentacion, why the budget had gone up..

http://office.microsoft.com/en-us/te...102930043.aspx

i wanna use this template, but there are several things i would need to change in order to fit it to my purppose..

the bottom line with days of the monts..i want it to be months.. jan, feb, mar ..etc
and the table have some formulas to preset de date that projects start and end, and when i try to change them, gives me warning

can anyone help me with this ussue? maybe walk me trough a little bit

im not an e xpert, but im trying to lear as fast as i can

hope to get a reply and thank you


PD: the ultimate goal would me to have the imfo in the attached file instead of the milestone, to show how much time we stored each of those items
im head cant take anymore