Before anything is ordered: survey and services
A proper survey checks wall flatness, floor level, existing service positions and whether the proposed layout is actually plumbable and wireable where it is drawn. Design software does not know where your soil stack is.
Getting this wrong is expensive later, because worktops and units are cut to the design, not to the room.
Strip-out and first fix
Strip-out is usually a day. First fix - moving water, waste and electrical circuits to the new positions, and any plastering that follows - is typically two to four days depending on how far services move.
Keeping sink and appliance positions unchanged is the single biggest way to shorten this stage.
Units, then worktop templating
Base and wall units go in once first fix is complete and walls are sound. Solid worktops are then templated onto the installed units, and there is a fabrication lead time between templating and fitting - commonly one to two weeks.
That gap is normal and unavoidable with stone or composite. Laminate avoids it because it is cut on site.
Second fix, appliances and snagging
With the worktop in, the sink, taps, appliances and final electrical connections go in. Expect a snagging list - door alignment, sealant lines, filler panels - and expect a genuine fitter to want to come back and clear it rather than rush it on the last day.