Go to www.minecraft.net then choose "Buy Now" if you haven't bought an account. Do what those instructions tell you. It will cost almost 30 US Dollars, but it depends where you are from. Buy an account, and sign in. If you already have an account, just skip Buy Now and go to Download Minecraft. Choose the link for whatever platform your computer is running on, then save the downloaded file, I prefer it on my desktop, them run it. The launcher will load. Sign in, and Minecraft will load. It should say, "Singleplayer," and "Multiplayer." Click Multiplayer. Click "Add Server," and under the box, "IP Address," type in the server IP of whatever server you wish to join. You can Google any IP. Some servers are white-listed, which means they must invite you to join. Most famous YouTuber's have their own server, and are usually public. Here is a list of a few IPs I know: 1. Mc.gg 2. Skyga.me 3. Uberminecraft.net. If you want to know how to MAKE your own server, that is a whole other story. I'm happy to answer that on a question somewhere else. Hope this helps!