Please try using google first. Here is a plugin that has a temp ban command: https://github.com/LegendOfMCPE/EssentialsPE (I think you use /tempban <player username>).
i already know essentialspe have tempban and i dont want such big plugin in my server while me only using tempban command...
@HittmanA try ModBanSystem https://github.com/BajanVlogs/ModBanSystem/tree/master/ /modban {player} {days} {reason} This is how you ban people thanks to BajanVlogs