Creating a user with a lot of data

I have trouble creating a user. I want all data from the form to create only one user. At the moment, after clicking the “add dj” button, the system creates one user without data from the checkbox, and after selecting the checkbox creates more users but only with data from the checkbox.

In addition, I want the checkbox fields to add several values to one column in the database, for example:
I mark in “Choose type of event”, option “Wedding”, option “Club” and option “Birthday”, a total of 3 options. I want the system to create a user as a result of such action, adding a few of these options to it, in the database and specifically in the “type of attractions” field.

Attached screenshot which shows the fields that are used to create the user.
How to do it?