Revamp Existing Advanced Multi-Form

We have a form already made, BUT the form has some issues. One, all of the fields are not required, so we would like that changed. Every time we submit each page with information, there is an SQL error that happens. We would like this form to have both an admin and client interface, as right now it is combined, so we would like the form to be submitted by each client, and for the admin to be able to access the information. We want this to interact with the database, because when it says artist, we want the artist to be pulled from the database. We are seeking the freelancer to be able to guide us on how to use the database, and assist us on how to deploy our app to the website - our website is coded in HTML and CSS and this web app is supposed to be external to our main website. We have reference videos available of how we wnat our main product to be, and our code will be posted along with this post as well. Amongst the system itself, there must be some changes that need to be made, such as bugs the developer has made, and given the fact that the project is mostly completed, we believe the cost should not be as significant, keeping in mind as well that we are on a budget. Thank you!