If you have never done any kind of substantive running, you have been away from running for a LONG time, and/or you are coming back from an injury it's likely you would be a good candidate for the 'Beginner' level training.
If you are relatively active and run periodically and
have perhaps completed a 5K or 10K here or there, 'Intermediate' may
make the most sense for you.
If you already run regularly 2-3 times/week
and have been for some time, 'Advanced' may be a solid training level
'Race' level is for folks who are ALREADY in the kind of shape
to run 13.1 miles and are primarily interested in becoming FASTER.
me emphasize that there are no hard/fast rules and feel free to toggle
between the various training levels.
Maybe you can only handle
'Beginner' level training the first month, but need something a bit more
challenging later on. NO PROBLEM! Try tackling the 'Intermediate' or
'Advanced' level training.
Your body will let you know when you are ready for something more demanding or if you need to dial things back.