The base is the whole job
We excavate to depth, lay compacted aggregate in lifts rather than in one go, and compact each lift. Depth depends on the soil and on whether anything heavier than furniture will sit on it. Skipping this is why patios move, and it is invisible on the day the last paver goes down, which is exactly why it gets skipped.
Cincinnati clay holds water, and water that freezes under a patio lifts it. Getting the base and the drainage right is not an upsell here, it is the difference between a patio that lasts and one that needs relaying.
Falls and drainage
A patio has to shed water away from the house. That fall is slight enough that you never notice it underfoot and decisive enough that rain does not stand on the surface or run back toward the foundation.
Where a patio sits below a deck, water coming off the deck above has to be dealt with as well, either with a drainage system under the deck boards or by grading the patio to carry it away.
Edges, steps and walls
Every open edge gets a restraint, because pavers with nothing holding the perimeter will spread and open joints over time. Steps up to a deck, seat walls, and fire pit surrounds are all built off the same base work and are far cheaper done at the same time than added later.
