Any tips for my database?

I have a form that consists of 3 dropdowns. The first is cartype- 200+ options. The second is seats - 6 options. The third is engine - 6 types.
I want to show in a bar chart only the SEATS - and how many have that many seats. So 6 bars that shows in the X-line the seat option(text) and in the Y the count of inputs for each option.
HOW??? I am getting the relationship all wrong each time…
I am really close to publishing but I need this one sorted.
And also I need my checkbox to work (if not checked then not register the input (GDPR accept))
Pls help!