The Save Baseline dialog has two options that are enabled if you select the Selected Tasks option: To All Summary Tasks and From Subtasks Into Selected Summary Tasks. These options control how the saving of a specific task's baseline information should affect the baseline values of the summary tasks that are "above" the selected tasks. If you select To All Summary Tasks, the baseline information for the selected tasks will affect all the summary tasks under which the selected tasks reside. If you choose the From Subtasks Into Selected Summary Tasks option, only those summary tasks that are selected with the selected tasks will have their baseline information changed with the saving of the baseline.
Saving a Baseline for a Selected Task
Select the tasks whose baselines you want to save.
Click the Tools, Tracking, Save Baseline menu item.
Select the baseline you want to save.
Choose Selected Tasks.
Decide whether you want to roll up the baseline information for the selected tasks up to all the summary tasks, or only the summary tasks that are within the current selection.
Select the tasks whose baselines you want to save. 
Click the Tools, Tracking, Save Baseline menu item. 
Select the baseline you want to save. 
Choose Selected Tasks. 
Decide whether you want to roll up the baseline information for the selected tasks up to all the summary tasks, or only the summary tasks that are within the current selection. 
Click OK. 
