See Here is a pic from my 87 ranger.
You can see that trim peace your talking about to remove it you will have to pull the three plastic bars under your dash trim you should be able to remove them with your fingers but you can use a flat head screwdriver if you like. After that is removed you will have 4-5 screws holding the dash trim on after removing the screws you should be able to remove the trim. The radio is held in with 4 screws and a clip in the back the radio should just pull out at this point. Also if you dont want to remove your headlight button you can pull on it (like your turning on your head lights) and this will allow you plenty of room to get at the screws. Good luck man just ask away if you need anymore help!