Koltin - print 5(or specific Number) random CharRange '0'..'z' and using + Operator to creat one new String

i ve been doing this Challage and stuck so hard. Yes, i did find a more easy way but its doesnt do the fullfill the Challange condition.

Condition: Create(Print) one String that have 5 or specific size of Character from a CharRange using + Operator.

little example

fun main() {
 val cRange: CharRange = '0'..'z'
 cRange.random()


}