Hello, so i have a heightmap i downloaded from the internet. I connected it to a uv project then a grid.
I know how to extrude individual colors by using the attributecreate node. I want to extrude the gride faces in relation the the values of the height map. How do I do it please?

If I understand correctly, the aim is to have each primitive in the grid extruded and to have the extrusion be scaled relative to the height map color for the corresponding grid primitive. If so, you might try the following using the current setup that you have in your screen capture:

Attribute Promote
-To promote @Cd from a point attribute to a primitive attribute.

PolyExtrude
-Divide Into: Set this to Individual Elements so that each grid primitive extrudes independently.
-Distance: Set to some value greater than 0.
-Local Control Tab > Distance Scale: Enable this local attribute and set it to Cd. This will use the color value from the height map to scale the extrusion Distance parameter that you set.