The server is the ip address of the computer that MySQL / Maria db was installed on.
If you are using the software and the database is located on the same computer the server would be localhost.
If you never setup the software before please see this video. https://www.youtube.com/watch?v=wqMbVtipuiU
To find the ip address of a server so that other computers using our software can connect to it open a command prompt on that machine and type ipconfig /all (then hit enter)
You will see the ip address the computer is on by looking for the ipv4 address as shown here.