I can't sculpt properly

I am new in Blender.
When I enter the sculpt mode, I cannot use my brush to make any difference even I adjust the strength into 10.
anyone understands what is happening?
Thx


Sculpting does by default not create new geometry, but rather moves the exisiting vertices. So, what’s supposed to happen when sculpting on a default cube?

Either check “Dyntopo” in the sculpting settings - that will dynamically create new geometry on the fly. Or massively subdivide your object before sculpting.

Also this isn’t exactly obvious, but in some cases it may also help to apply scale. So even if it’s being weird while still following the aforementioned advice, that could be it.

Thanks for helping me!