Inbox Rending when using External table
Hi there.
I'm finding it difficult to activate Inbox Rendering for our build of Campaign v6.1.
We have identified the external table used for targeting here:

But in the instructions from Inbox rendering, it asks me to "Extend the nms:seedMember schema and the linked input form to adapt the seed address definition mode to this target mapping." which is where I'm lost. How do I extend a schema?
Where is the seed address definition mode?