First off - this question is really broad and its scope could probably fill libraries. I will therefore limit the answer to generalized pointers in answer to your three sub questions.
Is there any place online where I can conduct an interview with Japanese people who reside in Japan and are familiar with their own culture.
Culture is a difficult concept. What I can say here is that every Japanese person is aware of their culture, because every Japanese is a part of their culture. Japanese culture is created by the Japanese inhabitants; it's what shapes them, it is the very air they breath. Conducting interviews is something that needs to be established and anthropologists often dive into the community of interest and spend considerable amounts of time to familiarize themselves with the culture, build a network and go from there. Understanding people, let alone their culture is not something that can be done easily from behind your computer screen I'm afraid.
How can I identify actions, activities, and goals of the culture in order to construct a meaning system so as to understand and interpret the relationship between the actors (culture), tools (e.g., appraisal of the child's actions), activities, scripts, and goals?
The first step is to develop a specific research question and subsequently operationalize it. I am reading diverse questions and here's just an excerpt from your comments:
...pinpointing some activities and understanding some of their goals. [...] Why is the expression of negative emotions discouraged in a Japanese society? What do mothers do to cultivate their child's cognitive development? Do they encourage verbal communication, eye contact, exploration, etc... Do they breastfeed? How long and why that long? How do they discipline their child?
You seem to be struggling with a lot of questions lacking the necessary research focus. Especially an undergrad study should be meticulously defined and most of all restricted to make it operable in the short time window available.
Do you have any tips on how to write an ethnography?
Libraries are filled on this topic. I can refer you to Clifford & Marcus, 1986.
Reference
- Clifford & Marcus, Writing Culture. The poetics and politics of ethnography. UC Press (1986)