I want to set up a server at home on Linux.

To be very rude, I don't have enough knowledge and experience to create an external public server when the question comes up.

You are aware that you are too amateur, so it is no shame that you do not have any knowledge or experience yet.You may not be familiar with terms like "fixed IP address" or "firewall".After you understand them, think about building an external public server.If you are the only one who suffers from unauthorized access by disclosing it to the outside world without understanding it well, you may cause trouble to others.Ignorance is a sin if that happens.

For now, let's think separately about building a server and making it accessible from the outside.You only need two PCs to build servers and clients on your home LAN.It doesn't matter if the server is left over or Raspberry Pi.The purpose is to learn how to build a server, so you can turn it on before using it and turn it off when you're done using it.It's not accessible from the outside, but learning to build a server is enough.

Once you've gained experience in how to build and security, you'll be able to make it public from a simple service.The first is the web server.You may need to sign up with a provider with a fixed IP address to get access from outside (not required for dynamic DNS services, etc.), but as you worry, it's better to rent a VPS instead of a home server for $3.5 per month.VPS also provides privileged users (root accounts), so you can run any service with knowledge.

The mail server is quite difficult, so please be prepared.If you are running a mail server, you will want to use the mail address of the domain name you have obtained, so you will also have to set up a DNS server.I think there are VPS services and domain name registrars that provide DNS servers, so it's a good idea to take advantage of them.

Even if you think you're the only one who can access it, if you make it a public server, you'll definitely be attacked.Resisting such attacks is also a highlight of your ability to operate servers, so gain experience.

By the way, sometimes people say that laptops come with an uninterruptible power supply because they have batteries, but I don't really trust them, so I don't know if they're suitable for home servers.In any case, considering that you don't have a line at home, I think it's a realistic course to first train at home LAN and then rent a VPS.

For now, servers are perfect, and if you have only one user, Raspberry PI will be a great server, and if you open it to the public and have more access, you will have to increase it, depending on the situation.

Setting up a server is nothing special because it's just a machine waiting for an inbound packet.If you do it on an independent LAN, you don't need security, readiness, or mental preparation.

A1. I have also built a server on a LAN that is not physically connected to the Internet.Your planned notebook is much more powerful than the commercial UNIX machine at that time.It might be cheaper to build a virtual machine on a slightly more powerful machine now.

A2. If you are the only user, it is sufficient to turn off and turn it back on each time.Once it's open to the public, it won't be easy.

A3. AP servers are Redmine, TestLink, WordPress, and so on.If you are the only user, there is no problem standing all at the same time with one (virtual) machine.Think about what to do when you need to scale up.

A4. Start with a fully independent LAN with no physical connection to the Internet.Then you don't need to connect to the Internet.TLS is likely to be needed if you want to be open to the public, and fixed global-IP address services are strongly considered.

You can learn the basics of so-called "infrastructure" technologies, such as DHCP/DNS/MTA/HTTP, even on completely isolated LANs without external connections (except for scaling and anti-attack protection mechanisms), and AWS is the only one who is bothered to do so.No problem with the free plan (so Oira will be a AWS driver)

1. Yes
2. Yes,
3. Yes,
4. I recommend you to pull the LAN.If it's a LAN, there's no communication cost.
5. There is no problem for one person to access it.

UNIX servers are broken and memorized.
Failure is the mother of success.Good luck.

If you want to install a Linux-based PC instead of a server, the first step is clear.
In the second step, you can't do anything with the box, so let's installing the software.
Here's the word Su.Linux has particularly noisy privileges.Even the TxT document I created myself must be authorized to open.Then you will learn commands such as chmod.
You will then try to manipulate Linux files using Explorer.However, Linux does not have such a convenient one, and uses commands or external tools.
Therefore, it is recommended that you learn how to use basic commands and proceed to build a server.

What about XAMPP?You can use the same environment on Windows and Linux, and as soon as you put it in, it becomes a server.