1. High Level
Aligned to your release model, details the major stages of a release: plan, build, accept and deploy and how the lower level activities fit within that: scope, requirements, build & test, acceptance, implementation, early life support and also show checkpoints (scope finalisation, build completion) and show gateways which align to your other processes such as governance, Change Advisory Boards etc). It’s also worth showing which environment various activities take place.
Build a timeline. Start from the ‘go live’ checkpoint at day 0, work backwards (T-) and plot in the major stages for an average release type (you may need one per model) and then plot other activity: environment management (data refreshes, interface switching etc), comms plan and enough lower level activity.
This high level lets you see the whole picture and start identifying areas of contention. If you have release cycles which last for several weeks and which are implemented monthly, you can expect some overlap. Examine these areas of overlap, it’s not uncommon to find the same teams doing different activities at the same time. Does this work for you?