How to understand all these domain name records?

Question

Domain Name System

Can someone here help me sort out all these records, especially the one that is red, is everything in order here, from the outside it seems like a mess.
The problem is that I can't help google index my site.
Initially, I requested indexing, confirmed the rights, entered the meta tag into the markup and created the same txt record in the domain name, right, after waiting only 3 days, not seeing the site in Google, I thought that I made a mistake somewhere, got confused, deleted all confirmation methods and html and on the txt server, I thought I’ll start again, though now Google can’t find the page, and when it comes to confirming the rights, Google answers,

although I deleted it =(

Answer 1

With domain records, it’s simple:
At what addresses your domain is available, access via ftp, smtp and pop protocols (this is about mail), ns - binding to hosting or to a domain, SOA record (Start of Authority) - initial zone record, which specifies the location of the reference domain record. It contains the contact information of the person responsible for this zone, the time the information was cached on the servers, and DNS interaction data. The SOA record is generated automatically.
With regard to Google, you are not the only one suffering, now many have this situation

Answer 2

Create and manage DNS zones. Part one
Creating and managing DNS zones. Part Two
Written a long time ago, but nothing has changed in DNS since then.

Answer 3

1. Snowflake is best removed if there are no automatic subdomains.
   
2. SMTP, POP and FTP are not needed
   
3. The last entry was wrong. Or specify only a subdomain or completely with a dot at the end
   

Answer 4

The second mx is not needed. You only have one server.