I've never used it myself. But I would have thought the example they gave was informative enough.
Lua Code:
local function bootlegRepeatingTimer()
print(GetTime()) >>> Code executed
C_Timer.After(1, bootlegRepeatingTimer) >>> Causes the function to occur again after 1 second
end
bootlegRepeatingTimer() >>> Start the cycle
This example is a timer of 1 second that calls itself making it a repeating timer.
Inside that function you could have it do what you want so that every 1 second ( in this example ) it will redo them. This can even be another function where you do all the functionality.