Two questions about domains?

I recently bought a domain and want to use it for a Minecraft server and website. I would like to know if and how it works to set this up so that I can use the same domain for both and don't have to buy a second one.
And now the second question. You know it: If you have a shop with a domain. To the domain in front to get to the shop or a forum. To get to the forum. I would like to know what it is first, or what it is called and, secondly, how it can be set up.

Thanks to everyone who helps or at least tries!

For a Minecraft server you set up an srv entry for the server in the DNS administration. Since every domain host uses a different method, contact your domain host or their help page.

Domains with a shop in front are called subdomains. You can create this in your hosting account if you have the opportunity. Depending on the hosting contract, you can set up a corresponding number of subdomains. Each corresponds to an independent domain that is only subordinate to your main domain.

A corresponding link or navigation tab is then set on the website, which leads to the shop and / or forum.

You don't need a second domain. If the web server and the Minecraft server run on the same server, i.e. Have the same IP address, you do not need a subdomain. If you want to use it, you can anyway.

I would have set up an A record for your domain that points to your server IP address. The prerequisite is that it is a static IP address. If you want you can create another A-Record with a subdomain to the same IP address or to a different IP address.

You should find exact instructions for adding DNS records from your domain hoster.

As long as the ports on the server are open, the Minecraft server should already be accessible under domain.

The web server probably still needs to be adjusted, as it differentiates between calling up via domain, IP address and domain with subdomain. Then you can also access your website via domain.

It may also be possible to use an srv record, but I'm not aware of it. I use A records on my server.

Due to the different ports of the Minecraft server and web server, the server can differentiate between the services for the same domain.