CRISPR makes genome-editing more accessible than it was before, because it's the only tool that doesn't require the engineering of DNA-binding proteins. Instead, it's targeted by base-pairing of a short RNA sequence, similar to a PCR primer.
That said, I'm afraid Research Gate may not be the right place to start answering how it all works and explain how to do it from scratch. It would be most efficient for you to start by studying the basics of CRISPR on websites like Wikipedia or Addgene. There's no point trying to re-write these excellent resources from scratch here in response to your post.
While you study these sites, you will come up with more specific questions, and I invite you to come back to Research Gate with those.