or you can use a distroplate and don't need a pump.
best for ryzen 9 and rtx3080
2 radiator 360 one above one below
then from distroplate into first radiator (front) and into rtx3080
then from rtx to cpu then back into top radiator then one into distroplate

Hoses, connections, a pump, an expansion tank, radiators (plus fan) and a CPU cooler.

In principle, you can also build graphics cards and graphics card coolers separately, but it may be easier this way.

One of the most important factors for watercooling is the choice of the case because it determines how many radiators you can install. What kind of case do you have?