Hi Paul, welcome to A.org - don't be too put off by the technobabble and use of jargon/acronyms.
Did the Amiga 500 you bought come with the TV modulator (you must remember from your old amiga) which you needed to connect it to a tv?
If not, then you either need to get one of these, or use a monitor capable of displaying amiga modes.
Hope you get it up and running.