Trouble defining my tables and their relationships

A little bit of context about the app:
On a school students go and weight recyclable materials (Plastic, metal, etc…) and a helper registers the material, the weight and the student.
The app will be used so these helpers can enter weights of materials for a specific student.

I’d like to have the following flow:

1- I look up a student and click on it, opening the details page
2- I see a list displaying the materials on the database (Metals, Plastics, etc…)
3- I select a material opening another details page
4- Within that details page I see a list displaying previous entered weights for the material and their register dates.
5- Within the same details page I have the button to enter a new weight by entering the weight in kilos and the register date.
6- On submit, the register should go to the respective material category and to their respective student.

I’ve been giving it some thought but I can’t come up with solid table relationships.
If this is not possible or there are easier ways to implement this I would really appreaciate new other approaches.
Thanks a lot in advance.