You need a 'TV Modulator' to attach a A500 to a TV using the standard kind of areil lead you may be used to attaching other computers and console with. These crop up on ebay from time to time. Again ebay is a good place for Amiga Scart cables although I am surePower Computing
must sell one. They still make and supply Amiga harware. Haven't looked myself though.
BTW you need more used tissues and a Monkey in the room.