Hi everyone, I hope you can help me to make this module
I have to create a form form with the classic fields name, email and up to here nothing difficult. In the form I would like to have two other fields with drop-down menus, where in the first field I enter a value (v) and depending on the value chosen in the first field, the second drop-down menu field must return me a series of values ​​(ah) which then the user will select.

example:
1 drop-down menu field: 12v, 24v, 36v, 48v, 60v
the second drop-down field must return a series of values ​​according to the number chosen in the first menu

If I select 12v, the following values ​​must appear in the second field: 8ah, 9ah, 10ah, 12ah

If I select 24v, the following values ​​must appear in the second field: 11ah, 12ah, 12.5ah, 14ah

and so on for the 36v, 48v and 60v range

The combination between the first drop-down field and the second field must give me a result in (Price in Euro)

The result (Price in Euro) must be seen in the automatic email that the user receives after clicking on the SEND DATA button on the form module

Combination example to understand:
12v (1 field) and 9ah (2 field) = € 189

I hope I was clear

How can I create this module?