Hi @Adam Geil
Definitely check out the video Mark posted in this thread. A good base example with the IT layer that I have seen to start with is one overall portfolio (let's call this Technology Services). The Tower (for example End User) would be your node. So in this case, it is pretty flat with one portfolio with the 11 Towers as individual nodes. The Sub-Towers align well to Service concepts and from there you can define your offerings. Given that Help Desk or Deskside Support is usually location based, you would have one Service to multiple offerings. Here is a screenshot that shows how the Portfolio, Node, Services, and Offerings come together in Digital Portfolio Management.
When you map a Service, the Offering dynamically inherets the portfolio and node. Depending on your maturity, organization size, and a few other variables you will want to review the approach including the number of portfolios, level of nodes, and types of services and offerings. To start with, I put these as Technical services, but there is good discussion and rationale of some topics to say should they be Business Services as the consumer is not the service owner, but the overall authorized user group. Many companies starting their journey will focus on one type of Service until they mature into other areas.
Hope this helps
