Inside your Autodesk Revit -based application, go to "AsiaSW" tab ⇒ "RoomMass⇒ "Generate" to start the command. Clicking this button starts the command and launches the "RoomMass" dialog.  

Under the left dialog you can filter select for phases and/or for level, in the right dialog select rooms that you want to process.

With mouse right click you can select/deselect all rooms

At the top you can specify:

• (Tessellate/Don't Tessellate) if you want to tessellate curve room's profile or not
• (Mass/Masses) if you want generate a single mass to contain all rooms selected or single mass for every rooms selected.
• (Tag/No Tag) if you want to tag automatically every mass with room name/ID that have generated it.

At the the middle you can specify:

( Room 2D) if your project is configured in Area and Volume Computations to Areas only (faster), you can extrude each rooms profile. Height is determined from Upper Limit and Limit Offset parameters of each room.

( Room 3D) if your project is configured in Area and Volume Computations to Areas and Volumes, you can choose to create extrude masses like previous option ( Room 2D), or to generate mass elements (mesh geometry) from each room volume.

If you select Room 2D, option Tessellate and Masses are disabled.

If your project is configured in Area and Volume Computations to Areas only (faster), Room 3D is disabled.

The installer that ran when you downloaded this app/plug-in from Autodesk App Store will start installing the app/plug-in. OR, simply double-click the downloaded installer to install the app/plugin.

To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer, and select the "Uninstall" button. OR, click Control Panel > Programs > Programs and Features (Windows 7/8.1/10) and uninstall as you would any other application from your system.

After installing the application you can use it for 15 days in trial mode, to give you sufficient time to get the activation code to unlock the use permanently.