First use the terminal or command prompt and use the ping command to check if you are able to ping the IP. Then you can use nmap to see which all ports are opened on that IP and also the OS which is being used.
ping -c 7 // For Linux
ping // For Windows
For MAC
When you see how it works you learn more about it. Below videos are of Linux but you get nmap for Windows and MAC as well if you are on Windows or maybe on MAC.
Download Link: nmap
Have Fun :).