Question Absolute beginner trying to write an easy grid shader?

Hi, as the title states, I'm very much a beginner in writing shaders.
I want to create a shader that creates this simple grid-like appearance:

I have scoured for good tutorials, but I thought it might be a good idea to post here to get help from more experienced programmers on how to approach this.

I am looking to use an Unlit shader with code being done in the fragment shader because I want to practice my coding rather than using the shader graph.

Thank you in advance!

 

Google "Unity Grid Shader" and you'll get a few thousand examples.

From there if you have questions about how a specific one works, please feel free to ask about that.