I am not with Laminar Research; just a flight simmer.
X-plane 10 and X-plane 11 are totally different packages. A lot of the 3rd party software packages produced for XP10 will not run in XP11.
A motor vehicle that operates with petrol will not run if you fill the tank with diesel and vice-versa. XP11 and XP10 falls into this category.
Make sure you don't install both packages into the same directory. If you install the software onto the desktop (recommended location) make sure they defined as XP10 and XP11.
My understanding is you will have to purchase a XP10 key as well for the software to run.
If you are new to X-Plane why have you downloaded XP10? XP11 is a more advanced product and easier to use, particularly when configuring hardware.
Hope this helps and gets you up and flying