I can create a Data relationship between my data extension, but I am not sure how do I use that data to run a campaign. Say Account and Orders are two different data extensions, I built a data relationship using AccountID. Now hwo do I use this relationship to prepopulate the information for my email templates or triggered send.
There are many ways you can use this -
You can create a filtered DE using this data relationship and then use this DE for personalizing your emails
You can also use AMPscript lookup function in your email to personalize