I have the pro series digital incubator model 4250

[Crysthianne]

I'm on the first day and the humidity is at 74% and the manunal is written that the level has to be 50-60% Does anyone know how to lower the level please?

 

[ChickenCanoe]

Remove some water or wait a few days and don't add any more water to see if it drops.
Humidity isn't an absolute number. In nature, humidity will fluctuate - sometimes widely.
The goal of humidity is to control weight loss during incubation. Eggs should lose about 0.65% weight each day on average.
It is possible to lose less than that for a few days and much more a few days later. You just want to get to that average by lockdown and then raise humidity in time for pipping.