[H4LLuC!N4t!0nS]

well hacking into a server can be done numerous ways. some of the ways are credential stealing through social engineering, credential stealing through an xss attack, or credential stealing through a phishing attack. and other ways such as just finding a vulnerability that has to do with file uploading that is unprotected. now these are not the only ways but these are some. oh i forgot to mention SQLi (structured query language injection). now on the topic of rooting a server. rooting a server is when you gain root (admin) access by unauthorized means. so probably the easiest way to hack into a server would have to be finding a vulnerability that has to do with an unprotected file uploading service and uploading what is called a shell. a shell will give you access to all the files in the system and depending on the shell can let you input certain commands in various languages into the web server. i hope some of the ideas listed in this reply will help you with your future adventure for knowledge