You need to understand the basic concept of how it works. Let me try and explain with example
Source Module with 3 dimensions - A, B & C
and Target module with 2 dimensions - A & B.
Now if you try to point and click in Target Module you need to have top level set for List C because Anaplan will map the common dimensions (A & B) and you need to tell Anaplan what should happen with the third dimensions which is not common between the two modules. Anaplan will aggregate the values on List C and pull the aggregated value, if you have a top level set and if you don't then it will throw an error.
You can also Use SELECT and LOOKUP to pull the Values - We Avoid using SELECT on list items but you can use SELECT on Top Level as it doesn't fall under production data.
You have tried to get month name as output ->>>>> You have achieved
But, based on what common similarity? you want to get the month name >>>> you have missed it
Again to your note: you have mismatch dimension between 2 modules
Step 1: I created a same mod 1 as you have created with simple list as dimension.
Step 2: I expect this should be your output.
Explanation of Line item :
List name : Purpose of this line item is to display all list item name.
Source List exists : Purpose of this line item is to check, is there any similar name between simple list and fruits list, and retrieving the similar list name which exists in simple list(which is a dimension in mod 1).
month cal: Purpose of this Line item is to fetch the month name based on source line item.
That is i am retrieving the month name based on simple list.