Actually, DNS the protocol is a horribly complex beast with various compression mechanism, tricky encoding rules, workarounds for MTU limits, etc. Most people "learning DNS" never even attempt to learn the protocol.

What is reasonably easy is a high-level understanding of e.g. "given this question, this is what one expects an authoritative DNS server to respond" in the human-friendly form, covering the basic kinds of questions (A/AAAA/MX/TXT/CNAME).