To play unblocked Minecraft games online, start Minecraft on your computer, add a new server, and then join it. To find servers, you must access a Minecraft server list online, and read descriptions until you find an open server you wish to try.
Once you find a server you wish to join, copy its IP address to your computer's clipboard. The IP address may be the server's domain name or a number. In Minecraft, click on Add Server, then click on IP Address, and paste in the copied information. Finish this by clicking Done. It is also possible to give the server a name of your choice.
Next, return to the main Minecraft screen, and click Multiplayer. Any servers you added are now listed. Click on the server you wish to join, and then click Join Server. If this does not take you directly to the server, you may be encountering a common error.
If the server says you are not whitelisted, it means that you must ask someone affiliated with the server for permission to join. If this happens, contact an administrator on the server's site to inquire about whitelisting. If it says you are disconnected by the server and that the session is invalid, restart your computer, and try again.
If the error says it cannot connect to server, the server itself is likely down. If the error says it cannot resolve hostname, it is possible that you entered its IP address incorrectly. Check the IP address, revise, and try reconnecting.