I have assumed that all the text input fields need to include strings with at least 3 letters. If the user enters less than 3 letters, a modal message will appear when the button is clicked.
Similarly, if any of the dropdowns are left unselected, a modal message will appear. If the user does not check the checkbox, a modal message will appear. If the user tries to enter a non-Turkish phone number (there shouldn't be a 0 at the beginning), a modal message will also appear.
If the user fills in all the fields correctly, they will be directed to a new web page.