It’s how many notes and how many measures

4/4 means there’s 4 notes in 4 measures like if you think about it in terms of rap, a sample is 4/4 if it repeats every 4 bars (I think) it’s been a while since I took piano

Music theory is some of the hardest s*** to explain lol

Here comes the sun, s*** switches time signature like 4 times in 10 seconds iirc