finalize dvd+r on logik ldvr78?

I have recorded some dvd's and they play on my DVD player , however when I tried to play them on another player they would not play. I then read the instruction book that came with the recorder and found that I had to finalize them. The book does not instruct you how to do this except for one tiny picture showing a menu from the disc edit menu and labelled PLAY. I can't get this menu up so what am I doing wrong. If I get this menu up with your help can I finalize the discs already recorded and if the answer is yes do I have to run them to the end of the film before I do it.