Spinner: list whose selection will be the key to choose, among others, a subsequent search list

Cheers to you all: I am a beginner.
I want to create a search, possibly with Spinner (alternatively I'm also trying with LastPicker), articulated as follows:
. a list of items; and so far OK with both; the following, the darkness...;
. The choice that is made will be the key to obtaining a subsequent search list;
. The result of this search will also be the key to getting another list.
I ask you for help because I can't go on.
Thanks in advance

I attach two images of what I wrote
MIT App Inventor B

You have to tie lists together in tables to link levels.

An example:

Thank you.
Tomorrow I will study the example and hope to move forward.
Tomorrow because in Rome (IT) it's time to go to bed. :smiley:
For now, thank you.
Anyway I'll keep you informed. :pray:

Later I will deepen the study of the bellismo gift that you have highlighted to me.
But I realized that I was not precise in my request: my problem is in inserting, in the Spinner the list of choices through "blocks" and not from "design": if for the first Spinner I could use "ElementsFromString", for the subsequent ones that are different for each choice, how can I do?
Thank you

PS from the image, what appears when I go to do with AI Companion debugging with mobile

index of "Select Iist Item" should be a number, not a string.

I try and I refer you :wink:

I am happy to inform you that I solved the problem of inserting in "ElementForString" of "Sinner" the list to be shown: I tried in many different ways and in the end this gave me the desired result.

I attach the images to be clearer

How big is this going to grow, that you have to code blocks for every choice?

You're absolutely right: but that's how it works. If you have any suggestions to lighten, please, let me know