Mass are quite easy to make but using this method might be require a lot of works.
How to make roof on revit.
If your design is quite simple you will not want to spend to much time on your roof.
On the draw panel click pick walls.
Select finish roof on the create roof footprint ribbon.
On the draw panel select a sketch or pick tool.
To edit roof properties before.
Draw a flat roof.
Changing slope angle and using slope arrow.
Create a roof by footprint display a floor plan view or a reflected ceiling plan view.
The second option in the list is toggle slope defining.
This option turns off the roof slope extrusion for the line.
On the properties palette set the underlay value to 01 store floor.
I will not discuss much about this for now.
Select toggle slope defining for each line of the roof outline.
First you can create a mass and create roof by selecting the mass faces.
Tutorial on roof construction modeling in revit.
Select the lines of the roof outline and right click over the line.
Click architecture tabbuild panelroof drop down roof by footprint.
Click architecture tab roof drop down roof by footprint.