Best Statistic Tool For Ranked Items

Hello to all!

I am in an introductory research subject, and this is is my first exposure to research. One requirement is for us to make a basic research. I chose the preference of buyers on online purchase, with the following questions:

1) Which e-commerce platform/s do buyers prefer when buying online. They rank the different platforms, 1 as the most preferred and so on.
2) What commodity do they buy through these platforms. They rank the different commodities from 1 to 3, according to preference.
3) What factors do they consider when buying. They rank the given platforms from 1 to 3 according to preference.

These are the samples of the results of responses I got from the google form questionnaire..

For the answers to the first question:

For the answers to the second and third questions, for the top three ranked platform. That is, a total of 6 tables: Commodity and Factor for each top 3 ranked platform.

Now my problem is, what statistical tool that I can use to:
1. That the top three platforms with the most number of preference can be said as truly representative of the preference of the sample? The professor said that I can NOT use frequency counts ONLY.

2. Establish relationship between the "platform" and the "commodity," because the goal of the study is to "prove" that buyers choose a certain platform for a specific commodity

3. Establish relationship between "commodity" and the "factor," because another goal of the study is to "show" that buyers choose what they buy depending on certain factors, such as price or reviews.

Any simple statistical tool will be appreciated, because as instructed, I can not just use frequency count. Thanks for any help to this old geezer.