If you hover over the effect in the left-side presets panel, the effect will be applied only as a preview. If you click on the preset, it will be applied to the image and you will see the settings in the right-side develop panel.
You can then alter a preset (whether one that ships with Lightroom, or one you might have purchased or created yourself) and save it as a new preset.
As an example, LR ships with Teeth Whitening. I personally find that preset to be too much - looks overdone in some images. I applied the LR preset, backed off the desaturation and the exposure, and then renamed that preset to "Teeth Whitening Half."
I am not sure we are talking about the same Presets.
I am talking about the ones on the right panel, that come up in Brush. I have none on the left panel.
I hover over the image and do not see any difference.
Also I have preset, again in the Brush/Right panel, that always comes up as the EFFECT. not Custom.
Evertime I go into to this , I have to go and select one of the LR presets, ,one the slider to just get back to Custom.
This is a lot of steps to get to Custom.
How do I get Custom or a neutral preset to come up so that I start with all sliders set to zero?