My sansung pn50a460s4dxza says it is 3d ready. how can i use this feature on my tv.

Your tv is a 2008 model, legacy 3d tv and requires a lot more than a current 3d HDTV does to view 3d. Today with a current 3d HDTV, Normally you only need a 3d source like a 3d Bluray movie and 3d glasses from Samsung and a HDMI cable connection from bluray player to HDTV. See below for your TV. You need a PC and IR emitter and Samsung 3d glasses plus user selected options on the tv.
Samsung 3-D Ready HDTV How do Samsung 3-D Ready HDTVs work?
Samsung 3-D Ready HDTVs are enabled by Digital Light Processing (DLP(R)) or Plasma Display Panel (PDP) engines that are capable of very fast refresh rates (120Hz). The inherent speed of these display technologies enables high quality stereoscopic 3-D by alternatively displaying left and right eye images. The display is synchronised with 3-D shutter glasses to provide the observer with a vivid perception of depth.
How do I connect my PC to a Samsung 3-D Ready HDTV?
The DVI output from the PC's graphics card must be connected to the TV's 3-D compatible HDMI port using a DVI-to-HDMI cable (or a HDMI cable plus a DVI to HDMI adaptor).
Alternatively, some newer graphics cards have a HDMI port instead of a DVI port. In this case, simply use a HDMI cable to connect the PC directly to the TV.
On all models, the 3-D compatible HDMI port is identified by the letters "DVI". (eg, "HDMI 3/DVI IN" or "HDMI 1/DVI IN")
What other equipment do I need to enjoy 3-D on my 3-D Ready HDTV?

• Windows PC with DVI output
• Compatible 3-D Shutter glasses and IR emitter with VESA compatible sync connector