Your message says you purchased a PS-CS6 with Lightroom package. The purchase options I am aware of are that you can buy PS-CS6 by itself or you can buy Lightroom and PS-CC as a subscription plan, but there is no PS-CS6 and LR package.
Which version of PS did you buy?
If you purchased LR+PS-CC then you should download the CC desktop manager app and install PS and LR from using that software. There is no serial number with a subscription, you merely need to be logged in to CC with the AdobeID you purchased the plan with.
If you’re not sure where to get the CC Desktop Manager from, then download the Adobe Application Manager from here:
If you have the CC Desktop Manger, already, then you can download PS and LR from here:
You might check if you received a redemption code for your purchase in your email. If so, follow the instructions here: Redemption Code Help
Once your membership is active you will need to license Photoshop CS6 for your subscription. This document explains the process Convert Creative Suite 6 applications to Creative Cloud membership
Like Ssprengel mentioned, Photoshop CS6 is not the latest version, there are actually two versions after that, Photoshop CC and CC 2014
To install Lightroom and later versions of Photoshop you'll want to install the Creative Cloud app which will allow you to install these.
This document explains the process:Creative Cloud Help | Install, update, or uninstall apps
Hope that helps,