Step 0: Once Installed the rSlope_Installer.msi, restart the Autodesk® Civil 3D® and hit the rSlope menu button loaded in the ribbon.
Step 1: Select a Start Pipe as Input
Step 2: Select an End Pipe as Input
Step 3or 4: either go with option1 or option 2 as your requirement.

The installer that ran when you downloaded this plug-in from the Autodesk App Store has already installed the plug-in. You may need to restart the Autodesk product to activate the plug-in. To uninstall this plug-in, exit the Autodesk product if you are currently running it, simply rerun the installer by downloading it again from the Autodesk App Store, and select the 'Uninstall' button, or you can uninstall it from 'Control Panel\Programs\Programs and Features' (Windows 7/8.1/10/11), just as you would uninstall any other application from your system.