How to install both programs.
I have both on my computer.
I use separate folders for my:
On my computer, those are subfolders of one I named MS System Files in my general Documents folder. Those locations are set for each version in File>Options>Advanced>File Locations (Button way toward bottom of dialog)
After you have both installed, run a Repair on the one you want to be your default for opening Word documents.
Do not install the Outlook from Office 2010 or uninstall it if you can.