Swing is a parameter that shifts the start time of off beat 16ths off the grid by a predetermined amount. We measure individual 16th notes in ticks, as in clock cycles :tick-tick-tick-tick-etc.
It can shift the start of an offbeat 16th note by as much 16% later - delaying a note by 8 ticks in the 16th note duration of 24 ticks. This equates to a 32:16 (2:1) tick length ratio for a pair of 16ths within the same 8th note space. This is effectively triplet 8th-triplet 16th pairs.
Other sequencers allow you to switch the swing out to 75%, which would be a 36:12 (3:1) tick length ratio. this is effectively dotted 8th-16th note pairs.
Use is down to taste. Most hip hop and rap use a swing factor of 66% - swing slider all the way to the right in FL. Some folks use swing to compensate for poor timing on playing notes in, others use it to compensate for mousing notes in.
Experiment with different swing factors and decide how you want to use it.
