Assignment Challenges with MS Project..A few more tips

Hi again,

Really in toruble with my overdue uni assignment..I would appreciate the help guys.

When I assign equipments(crane, excavator) to the project (From assign resources) it changes the project completion date

It is the same problem when I assign a regular meeting as well.

What can I do to keep the project duration same and change the project cost only when I add these cost into the project?

Thanks heaps

Seyma