Basic material nodes

I’ve never used material nodes before so I need a little help. My main basketball material consists of two textures. A custom made normal map that has those little round bumps and a procedural cloud texture that is also used as a normal map. I’m using the cloud normal map to deform the bumps. My problem is that the cloud normal map is also applied in between the bumps on the smooth ball surface.

What I would like to do is by using the compositor overlay a mask texture (where the bumps are white and black in between them) on top of the procedural clouds then use the result as a normal map. I just have no idea how I would do the nodes. I know that by using a mix node with multiply I can get the texture that I want to use as a normal map but I just can’t get my nodes working.

How do I grab a texture, edit it, and put it back in with nodes?