Log in to Partner Central, then look under the "Sales" tab.  Then find the "Solutions Enablement Toolkits".  Then look under "Infrastructure Virtualization Library".  The "VMware vSphere Plan and Design Service Delivery Kit"

is part of the Infrastructure Virtualization Library.  However, only certain partners have access to

"VMware vSphere Plan and Design Service Delivery Kit"

There are 5 pieces to the Infrastructure Virtualization Library and the

"VMware vSphere Plan and Design Service Delivery Kit"

SET is only one of them.  You don't get all 5 pieces automatically just for having a partner central account.  Your company must have a certain partner status and have the "Infrastructure Virtualization" competency before you will have the option to download

"VMware vSphere Plan and Design Service Delivery Kit"

However, if your company doesn't have the right status to be able to download it, check this link:

http://store.vmware.com/store/vmware/en_US/pd/productID.224267000/

That allows you to purchase the Infrastructure Virtualization Library directly from the VMware store.

In any case, the

"VMware vSphere Plan and Design Service Delivery Kit"

Solutions Enablement Toolkit has the best template I've found to use for mapping to the content of VCDX.

There is a word document in it called "vSphere Architectural Design".  That is the specific document in the

"VMware vSphere Plan and Design Service Delivery Kit" that gives you what you want.