it sounds like something really basic is missing to me.
1. Attaching a vCenter is not enough, that just creates a link between vCD to vCenter.
2. create a provider vDC associates Compute Resources (must be a DRS enabled Cluster) ... e.g. Creating a PvDC is like saying I want to Import a Cluster to vCloud Director.
3. Once you have that, then you can create an External Network (importing a Port Group that's available to all hosts in a given provider vdc ... aka cluster(s)).
4. Import Storage Policies, can be done inside the provider vDC itself or when you intially create the provider vDC. Setting up a Storage Policy is a whole process to itself. I'm sure google can assist there (I don't have a reference directly in front of me right now).