What exactly is your problem with playing it? Have you downloaded the client for your operating system (Windows XP, or MacOSX, Linux, etc.)? Have you double-clicked on the saved download and followed through with the installation? Have you attempted updating the client, then running it? The steps are fairly simple, and if you are having trouble with basic computer operation, then this is not the best place to begin your learning of how things work. Otherwise, can you please provide a more detailed account of what is stopping you from accessing the game? Are you aware of how downloads work?
Also as a side-note, Planeshift isn\'t meant for tens of thousands of players and I doubt it will be for a long long time. The game is still in pre-alpha stage, and many options and features are still in development.