Why I DO NOT SEE CF parent option & How to set automation rule to set cascading list? Edited

[Yana Nikolayeva]

Hi, my company is using Jira Core (Cloud) Standard plan

I have a need to set a cascading list of one of my custom filed.

Specifically:

CF1 has values: A and B

CF2 should be populated based on selection of value in CF1

If CF1 = A then set CF2 = 1,2,3 (where 1,2 and 3 is a list of values) 

If CF1 = B then set CF2 = 3,4,5

I was planing to configure CF1 as a parent and define the list of values from CF2  (as it is in attached screens).

I DO NOT SEE AN OPTION TO SET CF is a parent.

questions #1 -  IS it because it is not part of  Standard plan? 

questions #2 - if that option is not part of Standard plan, how I can use Jira automation rules to achieve the result? I found below example of code but not knowledgeable enough to convert it into my example

{
"update": {
"01": [
{
"set": {
"value": "{{triggerIssue.fields.01.value}}",
"child": {
"value": "{{triggerIssue.fields.01.child.value}}"
}
}
}
]

[Nic Brough _Adaptavist_]

Most of your question seems to be about how you would set up two select list fields as a cascading select.  Jira does not do this.

Have you tried using a field of type "cascading select"?  This would not need any coding or automations to behave as a cascading select.