Installation
Now that you have downloaded your desired server software, we can begin on installing and starting your server. Skip this step if you are using a hosting provider.
Installing Java
If you don't have Java already, you need to install it in order to run the server.
You need a specific version of Java depending on what you are running.
| Minecraft Version | Java Version |
|---|---|
| 1.7-1.16.5 | Java 8 |
| 1.17.X | Java 16 |
| 1.18.X-1.20.X | Java 17 |
| 1.21+ | Java 21 |
Download the specified version's setup by selecting your operating system (Windows, MacOS or Linux) and clicking on the download link. After it downloads, you should have a setup file in your downloads folder. When you open this file, it may ask you to trust the file before it installs.
On Windows, this is what it should show: 
Credit
Click on 'Yes' and it should install Java on your computer. After it is done, it should show this: 
Click 'Close' and you should be done with Java now.
Starting your server
Now that you have Java installed, it is finally time to start your server!
Place your server software file that you downloaded earlier into a new, fresh folder. I am using Purpur for this guide, but it should be the same for any server version: 
Now, rename the file to server.jar without any caps.
Create a new file in Notepad called start.bat and paste this in:
java -Xmx1024M -Xms1024M -jar server.jarMake sure that the file is a .bat and not a .txt by enabling file extensions in Windows: 
(in the 'View' tab in Windows 10)
After you have saved that file, open it using Command Prompt or Terminal. It should generate some files into the folder.
Accepting the EULA
Before the server is able to actually start, you need to accept the Minecraft EULA.
In the generated files, locate eula.txt and open it. In it, there should be a line that says eula=false. Change that to eula=true and you are all set!
Run the server.bat like before, and your server should actually load up and start now!
Joining the server
You can join this server on the same computer by typing localhost or 127.0.0.1:25565 as the Server Address or IP. Others on the same WiFi as you can also connect by typing in your computer's private IP found in Settings > WiFi.
However, others on other WiFi connections may not be able to join you if you haven't port forwarded. You may need to search up how to port forward on your specific router. You may also use a service like playit.gg to let others join without port forwarding.