Plex is a media playback system that makes it simple to share your movies, TV shows, music, pictures, and internet-based content. It uses a Server to house your media library and player Apps to playback the media. Technically, it's a Client-Server setup, but if you don't care for techno-speak, don't worry! What is important is that you understand the role that the Plex Media Server plays in a Plex setup. To understand that, let's first talk about your bank.
Banks are big users of Clients and Servers. When you visit a bank teller, the computer they have at the counter has some software installed that is a Client. The Client connects over the bank's network to its server which might be hundreds of miles away. The teller enters your account number and then watches as the requested information is provided by the Server. The PC at the local branch doesn't store any of your account details–they all come directly over the network from the server. In a similar way, you can access your account details using the bank's internet banking website. Your data is stored in the bank's server which you access securely using a web-based Client.
A Plex setup is similar to your bank–except for the obvious difference in scale! You install the Plex Media Server to a computer on your network, add media files to Libraries and let the Server fetch information about your library. Once that's done, install a player App (that's the Client in Plex-speak) to the PC in the living room, your mobile handset, children's tablets, etc. Connect the devices to your home network, and the Apps will automatically discover the Server and show you your media Libraries, ready for you to watch. Grab your mobile handset for the daily commute and the Plex Media Server is available (with a little more work) from over the internet. Like the bank scenario, the Apps don’t store information about your media but fetch it from the Server.
House your Media Library in a Central Place
A working Plex setup means you have to install the Server on a computer somewhere in your home. Without the Server, the Apps won't be able to playback any media. That might seem a little bit of a hassle, but the benefits it offers are huge. Seeing a working Plex setup for the first time is always a nice thing! Here's some of the key points:
A Single Library Means Easy Sharing
Adding an App to your Plex setup is simple. Install the App, launch it and watch as it discovers any Plex Servers on the network. The Server sends the App details about your media library, ready for you to watch. The nice thing about this process is that with the Server installed and running, you don't have to do anything more than that. It literally takes seconds to get an App up and playing media.
Having all your media housed by a central Server means you have a single place to manage your media collection. You might have some new movies to add, or don't like the poster image being used for your favorite TV Show. Every aspect of the Server is managed by the Plex Web App. It runs in a web browser from anywhere in your home, so you don't have to be at a particular computer to manage your library. Once a change is made, it's immediately available to all the Apps in your home without having to do anything extra.
Keep Track of What You're Watching
The Server keeps track of what you've watched, are in the progress of watching, and haven't even started yet. Each library item has a "watched" status indicator that lets you know that you have or haven't watched the show. Better still, if you half-watched a show it also remembers where you left off and offers to take up from there when you return to watch the rest. This happens on any App, not just the one you started watching on.
Keep Track of your TV Shows
You may have a favorite TV Shows you watch regularly. You might also like to know what's been Recently Added to the Server at a glance. The Server keeps track of what TV Shows you're currently watching and adds them to a handy quick-access menu called On Deck. On Deck is smart too. It includes the next available episode for a show after you've finished the previous one–great for TV Show marathons! If the next episode isn't available yet, the show will disappear from On Deck, only to re-appear once the next episode has been added to the library.
Keep Track of Multiple People (Plex Pass)
Because you can easily add player Apps, you're sure to have several people watching media from the Server. Avoid messing up each other's Watched and On Deck states by logging into your own Plex Account in your App. (This feature requires Plex Pass.)
There are many other benefits, but these give you a taste of a Plex enabled home.