OH3 GUI way to set up Item as the average of a channel over past 5 minutes

Setup, Configuration and Use Beginners
8

Here is how I calculate average rain every 15 minutes in the past 2 hours;

configuration: {}
triggers:
  - id: "2"
    configuration:
      cronExpression: 0 0/15 * * * ? *
    type: timer.GenericCronTrigger
conditions: []
actions:
  - inputs: {}
    id: "1"
    configuration:
      type: application/vnd.openhab.dsl.rule
      script: >-
        var work = OU_Weather_Actual_Rain

        OU_Weather_Actual_Rain_avg.postUpdate(work.averageSince(now.minusMinutes(120))as Number)
    type: script.ScriptAction

Hope this helps.