About GetWorldTimerManager().SetTimer

I cannot fully understand what GetWorldTimerManager().SetTimer’s parameters mean.
For example, in GetWorldTimerManager().SetTimer(Timer, this, &ATimerTest::print, 0.5f, true,10.0f);,
I cannot understand what 0.5f and 10.0f stand for. Is it correct that 0.5f means calling print function every 0.5 seconds? Also, is it correct that 10.0f means that after 10 seconds, we call first print function? Or calling print function 10.0 / 0.5 = 20 times?? I appreciate your helps.