Do you mean that you want to achieve the terrain in the second screenshot?
If you want to generate mountains, hills and rivers, you should combine multiple noise octaves( which are different noise values with different amplitudes and frequencies ).
For instance, To create realistic terrain, combine a noise octave that has really big frequency with another octave with relatively small frequency.
The terrain in the second screenshot is generated from simplex noise 3d
And I wouldn’t use this style of terrain even though it’s really cool, since it causes tremendous lag
And this is what i’ve done so far:
