I was asked to see if I could build a form for a child care website that takes care of the children during events.

I thought the form would be easy at first but I was asked if I can build the forms and a database to store forms for each event.
Also the client wants to be able to edit the forms for each event.

Just wondering where I should start on this.
The making of the form? Or the behind the scenes?
(Also, the client does not use a CMS for the rest of the built site but needs this to just be an add-on.)

Any type of pointers would be great since I'm fairly new to PHP.