If you are not too sure of the various detailed settings, then the best course is to select a preset that best matches your requirements from the list offered in the encoder.
My advice here is necessarily simplistic and assumes you are using the Export to DVD option in Premiere Pro.
In your case, try one of the PAL high quality presets - 4mb or 7mb CBR or VBR.
The more fast movement in your footage, the more useful VBR will be. If not too much fast movement, then CBR may be a better choice due to speed of encoding and, some say, better compatibility with DVD players.
Better to use 7mb unless the movie is too long, in which case drop to 4mb to get it all on one DVD.
The default audio setting is PCM, which is not very compressed. If you need to reduce disk space, try first using MPEG audio at, say, 192 k/sec. Access this option via the 'edit' button off the Encoding screen.
There is a lot more to DVD burning than the above, but this should get you started.
Come back if not.
