Help Needed from Non-Experienced Developer

Hi all, I'm trying to build a form that is connected to my files and folders in Sharepoint.

Here's how it works:

1. Employee goes to a Sharepoint site, navigate to the form page to upload marketing assets (jpeg/mp3/mp4/etc.).

2. Once uploaded, the marketing assets will be saved to the right folders according to the form field entries.

In other words, the form consists of drop-down lists that reflect the actual folder structure.

For instance, if I have the below folder structure:

Client Name > Campaign Name > Asset Name

The form will consists of 3 fields and 1 button:

1. Client name
2. Campaign name
3. Asset name
4. Upload button

I have no clue on where to start regarding this. Any tips?