The map is most useful when you enter it from a real problem, not from the beginning.
You are in an incident. Something is broken. Start at F3: which failure mode is this? Name it. Then use F7 to draw the failure path (not the happy path). Then use F5 to ask: which review question would have caught this before production?
You are in a design review. Something is being proposed. Start at F6: what archetype is this? That tells you which tradeoffs from F4 will dominate. Then run F5. Then use F3 as a pre-mortem: for each component, what is the failure mode if it is unavailable or returns incorrect data?
You are new to a system. You have a codebase, some documentation, and many questions. Start at F7: draw the five diagrams from what you can read. Gaps in the diagrams are gaps in your understanding. Then classify using F6. Then run F5 to find the failure surfaces.
You are in a career question. Should you take this technical direction? Apply F4: what tradeoffs does this choice make? Apply F9: which laws constrain what you can achieve? Apply F2: what principles does this decision preserve or violate?