The top figure shows how many notes in each bar and the bottom figure shows the value of those notes.

So 3/4 time has three QUARTER NOTES in each bar

4/4 has four QUARTER NOTES in each bar.

6/8 has six EIGHTH NOTES

2/2 has two HALF NOTES

So the value of the notes (QUARTER NOTES , HALF NOTES OR CROTCHETS , QUAVERS , MINIMS ETC etc) in the lower figure set the tempo of any piece of music.

Hope that helps