How to split single Directv input to 2 video inputs on HDTV+DVR box

You want to split the direct TV OUTPUT, not the input. But the direct TV tuner only tunes one channel at a time.
If you want to do that you need direct TV DVR and other direct TV hardware. Call the provider.

I think I worded this wrong. I have an old tv, not the new hdmi sort and I have been using it to watch dvds and jus today addeded two decoders for two satellite feeds and the tv only has the one set of input plug in spots and I was wondering if they make a plug that you can use so you plug it into the tv and then plug the other two sets of feeds, one for the dvd and the other for the decoders.

You need to get an audio video input selector that has the appropriate number of inputs and the correct type of video and audio connections for your TV.