Adding items without Results!! MSAccess

Hi,

I'm working since aloong time in the database that I attached, I did it in MSAccess, I have a big headache trying to figure it out..!! But nothing seems to work (or maybe I dont know how to do it)

The thing is that I have a Form(proyect) with a subform(item), in the subform will receive all the items pf a project, and then in the project form will get the total(the sum of all the items) but I can not make it work!!! And then I need to make a report per project.. isnt that hard.. isnt it? well, for me.. its the HUGE

Could you kindly look at it and help me with this?

Thank You very much...