Sometimes it can take quite awhile for them to hatch, if it's still trying I'd leave it be, I don't usually intervene at all (I have once). If you decide to this may be of some help Article 'Guide to Assisted Hatching for All Poultry'...
I was nervous my first time hatching too, who new you could spend so much time staring at an incubator🤣 But 80+ chicks later I still find it fascinating! Post pics when your littles hatch🥰
Is your hygrometer calibrated? I'm not familiar with this incubator, but if it has an adjustable air port that you can open and close if close it a bit and see if that helps, otherwise a wet peice of sponge should be fine. @Rose Quartz is right, the humidity will go up during hatching.