
For how music sounds, only the top number matters. If the top number is a 4 (like 4/4 or 4/8), then it sounds like this:
TA-ta-ta-ta TA-ta-ta-ta
A 3 on top (like a 3/4 waltz) sounds like:
TA-ta-ta TA-ta-ta TA-ta-ta
And a 2 on top (like 2/4 or 2/2) sounds like:
TA-ta TA-ta TA-ta TA-ta




The bottom number is just how you write a single beat.
If the bottom is 2, you write a beat as a half-note (𝅗𝅥). If the bottom is 4, you write a beat as a quarter note (♩) If the bottom is 8, you write a beat as an eight note (♪)
But it all sounds the same way. A beat is still a beat. This just makes is easier to write certain rhythms.