How to texture two images for displacement, overlay?

I can setup properly, this texture’s combined version but to get spike displacement it says I need to use not the combined but seperate textures, so how can I get those spike displacement to effect geometry?

Here is the texture: https://www.texturecan.com/details/257/

Use the mix rgb node set to add, and plug the textures into both rgb inputs.

thanks i’ll try that