through the Cantillon effect. any nominal amount of currency that is sufficiently divisible to facilitate transactions in the economy is enough, so at a certain point, the nominal amount does not matter. but the central bank can have a systemic influence on distorting the economy, e.g. through the Cantillon effect.
if Solvent imagines that all humans in the country suddenly woke up with 2x the money in their bank account, under their mattress, in their 401ks, value of their real estate, and so on, and all humans knew this had happened, nothing much would change. just the numbers, but all prices would quickly double as well.
but that's not what the central banks do. the money they "create" enters the economy through commercial banks and FRB. thus the banks get the new money first, and it might take a long time to trickle down to the last recipients (e.g. laborers or pension earners). thus the humans at the beginning of the chain can use their extra money while prices are still low, whereas humans late in the chain have to buy at the newly higher prices before they get any of the new money.
this is likely one reason why the banking and finance sector are so overblown in relation to the real economy these days. sectors that are close to banking (e.g. real estate) are also prone to being "blown up" artificially.