Sub-projects are used to split a large
project into smaller blocks. You can capture details of a sub-project such as
milestones,
budgets,
actions,
risks,
issues,
requirements and
defects, to name a few. You can also
attach documents to your sub-project or allow users to leave
comments on a sub-project.Sub-projects can be added from the
add menu in the top header area or the
Sub-projects tabbed view of the
project view page.On very large projects the sub-projects themselves can be split into multiple sub-projects.
Sub-projects are used to split a large 
project into smaller blocks. You can capture details of a sub-project such as 
milestones, 
budgets, 
actions, 
risks, 
issues, 
requirements and 
defects, to name a few. You can also 
attach documents to your sub-project or allow users to leave 
comments on a sub-project.Sub-projects can be added from the 
add menu in the top header area or the Sub-projects tabbed view of the project view page.On very large projects the sub-projects themselves can be split into multiple sub-projects.