Hi Gail i've taken the liberty looking at your question and copied it into the catagory Video under subtitle video and standard tv section of the forum keep looking in that section as well for replies.
Start from scratch Plug the airial directly in to tv see what you get.
Then remove aerial plug from TV and plug it into 'in' on white box.
Then TV link cable to 'out' socket the other end to TV. A signal booster should be mains powered so If this box has mains plug plug it in to 13amp socket then check for 'on' switch or if red neon light is on. Can't say much else.
Keep looking in this and the video standard TV section near bottom of forum.
nobby
January 2009