Probably this is confusing you:

1 tick = 1 / 16 seconds = 62.5 milliseconds.

It means that one second has 16 ticks. So 1 Tick is one sixteenth of a second, which is (1/16) second = 0.0625 seconds = 62.5 milliseconds.

I guess the strange "tick" unit stems from old times where games used to run with about 16 fps.