What does the different beat mean

I know next to nothing about music, but what I am trying to understand is Bob's different style of playing. From what I am reading in "Chronicals" is that he uses a 3 beat mixed with a 4 beat. I am a roller figure skater and sometimes skate to dances and I can count beats ok. I'm wondering if an example of what I am hearing is like in the song "Long and wasted years", you can count 4 beats real slow or 3, 6 beats fast at the same time. In "Tempest", the 3 beats between each of the 4 beats is easy to follow, like a waltz mixed with a 4 beat song. Like I said, I know nothing about music and am just guessing here. Any help or ideas?