How to setup burstable bandwitdh!

RouterOS Beginner Basics
1 
minimum - maximum
64 KBPS  -  256 KBPS

I have this option in new usermanager
Rate limit: Rx Tx
Burst rate: Rx Tx
Burst threshold: Rx Tx
Burst time: Rx Tx
Min rate: Rx Tx

how to assign this speed to them?