Connections. I have a simple TV it does not have a TV/VIDEO button to push,I have to use a RF

Question

I have a simple TV it does not have a TV/VIDEO button to push,I have to use a RF modulator to hook up my other dvd player This TV only has a singel connection for a cable hookup(no audio/video connections) so I use the RF modulator for the dvdplayer I have now (I use the S-video and the red and white audio now), I disconnected the other dvd player and hooked up the new one with the cables supplyed with the player and get nothing I dont have a TV/VIDEO button to push as the instrutions say to do.How do I hook this up using a RF modulator and no TV/VIDEO button to push?