[Semibug] domain name management novice

[Dr. Robert Meier]

Semibug,

I recently registered a domain name.
I am interested in learning how to manage it effectively.

What is the best way to learn how to manage a domain
	with registrar-provided remote access tools?
What are basic expectations?
What are some advanced expectations?

What are best practices regarding
	 'A records', 'A dynamic records', 'mx record',
	 'URL redirection', 'ABE', ???

I've been a sendmail and postfix postmaster, apache webmaster,
	and moinmoin wikimaster for most of the last 4 decades.
I've edited ldap, nis hosts, and iptables set up by others.

My goals include
	1. /var/www/html/index.html
                 on my (Raspberry Pi) web server
		is seen by the public as https://mydomain.tld/
			also as https://www.mydomain.tld/
	2. port 1465
                 with listening (Raspberry Pi web server) postfix
		is seen by the public as mail.mydomain.tld:465
	3. /var/www/purpose/index.html
                 on my (Raspberry Pi) web server
		is seen by the public as http://purpose.mydomain.tld/
			also as https://www.purpose.mydomain.tld/
	4. port 80
                 on my hot tub web server
		is seen by public as https://hottub.mydomain.tld:8080/
	5. Other hosts on my LAN are visible to each other,
		but invisible to the public.

I currently have approaches to meet all of the above goals.
1 and 3 have been successfully tested.
2 and 4 are untested.
5 is not known to fail (which is not the same as successfully tested).

I believe that there are BETTER approaches than what I have devised.

Thanks in advance,
--
Bob