Performing top-down estimations using prior experience (P6 Professional Only)

Choose Tools, Top Down Estimation.
Choose to estimate labor or nonlabor resource units.
In the WBS field, click the Browse button to select the WBS element whose activities you want to estimate. Click Select.
In the Resource field, select the resource to estimate activities assigned to a specific resource within the specified WBS element. Click Select.
Choose Prior Experience.
Enter the estimate in the Estimated Units field.
Mark the Apply adjustment checkbox to apply an adjusted percentage to the estimate. Type the adjustment percentage. For example, if the estimated units are 400.00h and you apply an adjustment of 50%, P6 Professional will add 200.00h (50% of 400) to the estimated units. The Adjusted Units field will display 600.00h.
Click Save As to save the estimate without applying it. Type a name and any assumptions and notes about the estimate, then click Save.
Click apply to perform top-down estimation. Click Yes when prompted to confirm that you want to apply a top-down estimate to the project, then Click OK.