Shader Forge help: interactive surface.

Hi, i'm an artist with some technical background, but not much : ) as in if you want to get technical with your help, feel free i'll try and keep up.

i'm learning shader forge to help with my custom shader creations, its been great so far and i've had some success teaching myself but i've come to a point where guidance would be really helpfull.

i need to create an interactive shader, think a water's surface that generates ripples when touched.
i'm able to create the graph that creates the ripples, but i'm not sure how to go about making it reactive and change the origin of the wave based on outside input.

any hints to where i should direct my attention to would be appreciated.