Using arrays calculations in Excel.

In a rather complex Excel spreadsheet that I am studying to apply it, I came across a calculation step that uses arrays in such a synthetic way that I cannot decipher.

I looked on the internet and with Copilot for this calculation system, but no one has hit the nail on the head with this particular calculation solution.

In essence, in the spreadsheet there is a drop-down combo box with a list of elements for which the spreadsheet determines the static characteristics of each element chosen.
In another part of the spreadsheet, a one-dimensional array has been inserted vertically showing all the elements listed in the cell with the drop-down combo box and next to each of them the value of a certain coefficient depending on the type of element chosen in the drop-down list.

The spreadsheet reports the analysis of only one element, the one chosen in the drop-down box, while the array calculates and reports the coefficient in question for all the elements inserted in the drop-down list.

To fix the ideas, I report on an excel sheet the situation extracted from the context for greater clarity hoping that someone can recognize the steps used and explain them to me in a linear way because I am not familiar with the use of arrays in excel.

Thanking in advance the people who want to help me understand the problem, I send cordial greetings to everyone.