How to compare and extract data from two CSV files?

I have a large number (50+) of CSV files of user inputs. I would like to pull out the inputs from a subsets of the users. The data files look like this:

A@gmail.com, data1, data2, ... , data15
B@gmail.com, data1, data2, ... , data15
...

In particular, every file has the same number of entries. The csv file of subset of users to be pulled out looks like this:

K@gmail.com
L@gmail.com
W@gmail.com

and I want to extract the entries for (say) data2, data3 and data7. What is the best and simplest way to do this?

Note:

This question is similar to my previous inquiry but are different, so following forum rules I post this question.
This is a one-time task; I have asked the source to turn these into a database in the future.
I use LibreOffice, in case that matters.

To clarify:

Entries of the CSV files are comma separated. None of the entries have quotation marks, and the entries for the dataN cells are decimals (e.g. 20.0).
The header row of the data files are:
```
Email,Set1,Set2,...,Set15
```
To explain what I meant by “extract”, let’s say my raw data file looks like this:
```
A@gmail.com,1.0,2.0,3.0,4.0
B@gmail.com,5.1,6.1,7.1,8.1
C@gmail.com,10.3,11.4,12.5,13.6
```
Let’s say my subset of users consists of
```
A@gmail.com
C@gmail.com
```
And let’s say I want the entries for the second and third data points. Then the outfile I need is
```
A@gmail.com,2.0,3.0
C@gmail.com,11.4,12.5
```