Unity 3D C Sharp Coding For Web-Based Interactive Art Work

Hello, I am working on a piece of art work that is discussing the plastic crisis our oceans are currently suffering with. I have built a 3-D environment and scenario that allows the player to move around a beach with the objective of fulfilling the mundane task of picking up litter. The level design is finished (please see attached photos) but what I can't finish is the coded elements in the project. For example: when the litter is picked up and moved to a certain location, writing on the UI tells you you've collected 1/15.
The project doesn't have an incredible amount of coded work to be done but I can't get my head around C Sharp.

If the project goes well on the freelancer's end and I'm happy with the result, I'd like to create a longer dialogue between us for future (similar) projects on the horizon.

For a list of the C Sharp actions and more information please don't hesitate to ask.

Thanks a lot in advance,
Henry