The tree reads top to bottom in four layers. At the root sits a single desired outcome — a measurable goal the team is chasing, such as lifting activation or reducing time-to-value. Below it branch opportunities: customer needs, pains, and desires expressed in the customer's own terms, surfaced through continuous discovery. Below each opportunity sit candidate solutions, and below each solution sit the assumption tests or experiments that probe whether the solution will actually move the opportunity.
The structure is deliberately a tree, not a list. A single outcome forks into many opportunities, each opportunity into several solutions, each solution into multiple tests. This branching forces a team to hold more than one option at every level, which is the antidote to committing to the first idea that sounds plausible.