So at it's most basic. The process 1) Starts in Cloudflare. You'll go DNS > DNS Settings. Enable DNSSec.
Cloudflare will then give you the "DS Record" that you will need to input with your Registrar. Cloudflare will give you the record all in 1, but, then it will break down the information below that.
DS Record = full record
Digest, Digest Type, etc etc, breaks down that record in an easier way for you to view it.
You'll need to plug that into your Registrar. FYI, your registrar may not require each and every one of those values. Which is why it's so difficult for me to give any more specific info.