Hi,
the best way is explained here: https://www.easy-profile.com/support/adding-columns-to-member-table.html#reply-6654

if you want to manage 5 column from Menu item parameters the way you wrote seems correct, only one thing, a the end of your code in file /components/com_jsn/views/list/tmpl/table_user.php miss endif statement, so you need to add:

<?php endif; ?>

We have choosen to limit to 5 columns for responsive purpose.

ok,

Do I really need to coopy to com_jsn in my template? I think isn't necessary.

No this is not necessary, but if you update easy profile, all template files will be overwritten. This does not happen if you use the template override.

doesn't help me at all because I don't want to show that on every user-list, I only want to pick some.

ok, I will send you table.php table.xml and table_user.php files with instructions , please wait 2 hours

I want to allow new columns in administrator (backend) and not just put it by force on frontend.

Sorry this is not possible with Easy Profile, Easy Profile extends Joomla user profile where this is possible. Joomla not allow you this thing with plugins. To do this you need massive customization of Joomla core files.

Hi,
here the files, copy into /components/com_jsn/views/list/tmpl/

I think you didn't understand me hehe, I didn't ask for extra fields on users backend by joomla, I was asking backend in Easy Profile when you do this:

1. Edit/Create menu item (Menu Manager)
2. Select type User List Table
3. On third tab (Table)
4. Add 6th column to Enable column 6.

ok we will add in next release.